JPH06209268A - Tuner device and on-vehicle ratio receiver using it - Google Patents

Abstract

PURPOSE:To obtain a structure which is capable of effectively preventing the radiation of spurious higher harmonics from the local oscillator within a front end circuit and performing an adjustment under almost the same condition as a practical use with only a front end device or tuner device. CONSTITUTION:In a tuner device 40 changing an antenna input signal into a sound signal, tuner circuit parts 44 are mounted on a tuner substrate 42 and a shield case 50a enclosing front end circuit parts for FM wave composing the high frequency amplifier circuit, the mixer circuit and the local oscillator circuit of these tuner circuit parts 44 are provided. On the tuner substrate 42, an antenna jack 20 composed of a cylindrical body for earth 20a and the signal terminal 20b insulated by this cylindrical body for earth 20a is mounted. The signal terminal 20b of this antenna jack 20 is connected with the signal pattern for the antenna input of the tuner circuit substrate 42. The cylindrical body for earch 20a of the antenna jack 20 is press fitted into a jack mounting plate 52 composed by extending the part of the shield case 50a and is supported by the plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tuner device capable of accurately performing tracking adjustment and preventing radiation of an unnecessary frequency from a local oscillator of a front end circuit, and a vehicle-mounted radio receiving device using the tuner device.

[0002]

2. Description of the Related Art In a radio receiver having an FM receiving function, an element composed of a high frequency amplifier circuit for FM reception, a mixer and a local oscillator is called a front end. It is mounted on a single board and shielded by a seat plate, and in particular, it is shielded from the radio output signal to prevent interference and oscillation.

It is necessary to guide an antenna input to this front end circuit, and for example, in the case of an on-vehicle radio receiver, the configurations shown in FIGS. 4 and 5 are adopted.

FIG. 4 shows a structure in which the antenna jack 70 to which the coaxial cable 72 is connected is attached to the rear surface 76 of the chassis 74. At this time, the coaxial cable 72
Is fixed to the rear surface 76 of the chassis 74 with screws using the mounting bracket 80. The insulating skin layer of the coaxial cable 72 is peeled off in a region corresponding to the cutout portion 82 formed in the mounting bracket 80 to expose the internal wire 72a. The exposed wire 72a is soldered to the fitting 80 to connect the antenna jack 70 to the ground.
The signal terminal of the coaxial cable 72 is to be soldered to the pin on the board arranged in the chassis 74.

FIG. 5 shows a structure in which the antenna jack 90 is directly attached to the main board 100. The antenna jack 90 includes a grounding tubular body 90a,
Signal terminal 90 insulated from this grounding tubular body 90a
b. The signal terminal 90b of the antenna jack 90 is soldered to the signal pattern of the main board 100, and the grounding tubular body 90a is supported by a mounting bracket 92 fixed on the main board 100.
The mounting bracket 92 has a jack press-fitting plate 94, and supports the grounding tubular body 90a by press-fitting. The mounting bracket 92 further has a mounting piece 96, which is fastened and fixed to the rear surface 76 of the chassis 74 by screws 98. On the other hand, a front end pack 110 is mounted on the main board 100. The front-end pack 110 has at least a high-frequency amplifier circuit for FM, a mixing circuit, and a local oscillation circuit on a substrate 112 supported in a shield case 114.

[0006]

In the conventional structure shown in FIGS. 4 and 5, it is possible to effectively prevent so-called unnecessary radiation in which the transmission output from the local oscillation circuit in the front end pack leaks to the outside. There wasn't.

According to the structure of FIG. 4, the ground terminal of the coaxial cable 72 is connected to the chassis 76 by the mounting bracket 80. On the other hand, the ground pattern of the front end circuit finally reaches the ground potential via the chassis 76, but the ground potential of this front end circuit and the potential of the chassis 76 are different. This is because a relatively long ground line is formed between the ground of the front end circuit and the chassis 76, and this ground line has a high impedance. Further, the signal terminal of the coaxial cable 72 is also connected to the antenna input terminal of the front end circuit via a relatively long signal line.

As described above, since the impedance of the ground line at the antenna input section increases and the signal line for antenna input is also long, the oscillation output of the local oscillator circuit radiates to the outside from the long signal line. As a result, so-called unnecessary harmonic radiation is generated. This causes radio interference.

On the other hand, also in the structure shown in FIG. 5, the ground line and the signal line of the antenna signal are formed along the long pattern formed on the substrate 100, and the impedance of the ground line is high because it is a thin film pattern. . Therefore, in practice, as shown in FIG. 5, the mesh wire 1 is provided between the shield case 114 of the front end pack 110 and the grounding tubular body 90a of the antenna jack 90.
Unless 16 was fixed by soldering, the above-mentioned unnecessary radiation of higher harmonic waves could not be prevented.

Another problem shown in FIGS. 4 and 5 is that when the front end circuit alone is used for tracking adjustment and the like, it cannot be performed under the same conditions as the actual use conditions. That is, in both cases of FIG. 4 and FIG.
When the front end circuit is adjusted as a single unit, the antenna jack 70 or 90 used in the actual device is not connected. Therefore, normally, the antenna input pin must be set up on the board of the front end circuit, and the adjustment must be performed while inputting the antenna to this pin.

Therefore, an object of the present invention is to effectively prevent unnecessary harmonic radiation from the local oscillator in the front end circuit, and to use the front end device alone or the tuner device alone. Therefore, it is to provide a structure that can be adjusted under substantially the same conditions as the actual use conditions.

Another object of the present invention is to provide an in-vehicle radio receiving device which requires almost no readjustment of tracking after the tuner device having the tracking adjustment is incorporated into the main body of the device.

[0013]

Means for Solving the Problem and Its Action The present invention is
In a tuner device for converting an antenna input signal into an audio signal, a circuit board on which a ground pattern and various signal patterns are formed, a tuner circuit component mounted on the circuit board and connected to the signal and ground pattern, and the tuner. A signal input / output connector mounted on a circuit board and fixed to the tuner circuit board by being connected to the ground pattern, and constituting a high frequency amplifier circuit, a mixing circuit, and a local oscillation circuit of the tuner circuit components. F
A shield case surrounding the front-end circuit component for M waves, a grounding tubular body, and a signal terminal insulated from the grounding tubular body, the signal terminal being a signal pattern for inputting an antenna of the tuner circuit board. And a jack mounting plate configured to extend a part of the shield case and press-fit and support the grounding tubular body of the antenna jack.

According to the present invention, the antenna jack is mounted on the same substrate on which the front end circuit is mounted. And by connecting the signal terminal of this antenna jack directly to the antenna input pattern on the board,
The distance from the signal terminal of the antenna jack to the antenna input terminal of the front end circuit, that is, the distance of the signal line can be set to the shortest. Further, the grounding tubular body of the antenna jack is press-fitted and fixed in a shield case having the same potential as the ground potential of the front end circuit. Therefore, the ground line of the antenna input section becomes shortest, and the impedance of the ground line formed by the shield case having a thickness sufficiently thicker than the substrate pattern can be sufficiently lowered. Since the impedance of the ground line can be reduced in this way, unnecessary harmonics from the local oscillator in the front-end circuit can be radiated from the signal line with a relatively short distance as described above. Disappear.

Further, according to the present invention, by disposing the antenna jack on the same substrate on which the front end circuit is mounted, this antenna jack can be used when adjusting the front end circuit. Therefore, this front-end circuit can be adjusted under almost the same conditions as the conditions in which this front-end device is used by being placed in various types of equipment, and adjustment can be performed in a stable state, resulting in a large amount of erroneous adjustment. It can be reduced.

In the tuner device of the present invention, the tuner circuit board further includes a first circuit board on which the antenna jack, the front end circuit component and the shield case are mounted, and an F circuit other than the front end circuit component.
The connector mounted on the tuner circuit board is provided on the first circuit board, and has a cutting portion that can be cut into a second circuit board on which tuner circuit components for M waves and AM waves are mounted. The first connector and the second connector mounted on the second circuit board.
A signal input / output cable between the second circuit boards is provided.

According to this structure, the first and second circuit boards can be integrally formed, and the parts can be automatically inserted, automatically soldered, and tracking-adjusted. By dividing into the first and second circuit boards, they can be arranged at different positions. Therefore, the degree of freedom in the layout of the circuit board in the device body is expanded.

Further, in the tuner device of the present invention, the front-end circuit component includes a variable capacitance diode for FM wave tuning, the capacitance value of which changes according to an applied voltage.
The wave tuner circuit component includes a variable capacitance diode for AM wave tuning, the capacitance value of which changes according to an applied voltage, and the tuner circuit board has a voltage applied to each variable capacitance diode for FM wave and AM wave tuning. A memory for storing corresponding tracking data for each of a plurality of types of frequencies, and a constant voltage power supply circuit for setting a reference voltage of a voltage applied to each of the variable capacitors are mounted, and the connector is connected to each of the variable capacitors. It is characterized by including an input terminal for an applied voltage, a data input / output terminal for the memory, and a voltage output terminal for the constant voltage power supply circuit.

With this configuration, the voltage serving as the reference of the voltage applied to the variable capacitance diode can be set by the reference voltage of the constant voltage power supply circuit in the tuner device both during tracking adjustment and in actual use. Therefore, almost the same sensitivity as when the tracking adjustment is performed can be obtained even in the actual use state. As a result, it becomes almost unnecessary to change the tracking data after storing the tracking data unique to the tuner device in the memory in the tuner device during the tracking adjustment.

The on-vehicle radio receiver incorporating the tuner device having these characteristics can also utilize the characteristics of the tuner device as it is, almost no readjustment of tracking is required, and unnecessary radiation of harmonics is eliminated. Further, if the tuner circuit board is divided into the first and second circuit boards and arranged in the chassis, the degree of freedom in layout of components in the chassis is expanded.

Further, since unnecessary harmonic radiation is a problem for the front end of FM waves, the front end circuit and the antenna jack may be mounted on a single board.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tuner device to which the present invention is applied will be specifically described below with reference to the drawings.

FIG. 3 is a block diagram of the tuner device according to the embodiment. The present embodiment shows a tuner device built in an in-vehicle radio receiver, and an antenna plug 12 connected to an antenna 10 is provided on the vehicle side. The tuner device mounted in the in-vehicle radio receiver is provided with the detachable antenna jack 20 on the antenna plug 12. A high frequency amplifier circuit 22 for inputting an antenna signal input from the antenna jack 20 is provided. Further, a mixing circuit 24 that mixes the output of the high frequency amplification circuit 22 and the output of the local oscillation circuit 26 and outputs an intermediate frequency is provided at the subsequent stage of the high frequency amplification circuit 22. In general, the high-frequency amplifier circuit 22, the mixing circuit 24, and the local oscillation circuit 26 described above constitute the front-end circuit 21.

When the reception frequency output from the high frequency amplifier circuit 22 is fr, the oscillation frequency from the local oscillation circuit 26 is f0, and the intermediate frequency is fi, the oscillation frequency oscillated from the local oscillation circuit 26. f0 becomes f0 = fr ± fi. Oscillation frequency f0 from this local oscillator circuit 26
Is fixed by a PLL circuit (not shown),
By mixing the frequencies f0 and fr in the frequency mixing circuit 24, the intermediate frequency fi is output from the frequency mixing circuit 24. As described above, the front end circuit 21 including the high frequency amplifier circuit 22, the mixing circuit 24, and the local oscillation circuit 26 has the antenna jack 2
It converts a high frequency input signal from 0 to an intermediate frequency signal.

In the device of this embodiment, in addition to the front end circuit 21 described above, the following circuits are built in the tuner device. That is, in the subsequent stage of the mixing circuit 24, F
An M intermediate frequency circuit 30, an FM detection circuit 32, an FM noise canceller 34, and an FM multiplex 36 are provided, respectively.
The signal and the R signal are output. The above circuits including the front end circuit 21 constitute a tuner circuit 28 for FM waves.

Further, the tuner device of the present embodiment is AM
A wave tuner circuit 38 is also built in. The AM wave tuner circuit 38 is designed to receive an antenna signal from the antenna jack 20 and output an AM detection signal to the FM multiplex 36.

Next, the structure of the tuner device incorporating the above-mentioned circuits will be described with reference to FIGS. 1 and 2.

The tuner device according to this embodiment is constructed as a tuner pack 40. The tuner pack 40 includes a tuner board 42, an antenna jack 20, a component 44 constituting each of the circuits, a connector 46 for connecting to another board, and a shield case 50.
It is equipped with.

The shield case 50 is divided into two parts, and the first shield is formed so as to cover the regions of the above-mentioned high frequency amplifier circuit 22, the mixing circuit 24 and the local oscillator circuit 26 which constitute the front end circuit 21. Case 50
a and a second shield case 50b formed so as to cover the regions of the other circuits. The antenna jack 20 is press-fitted and supported by a jack press-fitting plate 52 formed by extending a part of the first shield case 50a for the front end. The antenna jack 20 includes a grounding tubular body 20a and a signal terminal 20b insulated from the grounding tubular body 20a.
This portion is press-fitted and supported in a press-fitting hole 54 formed in the jack press-fitting plate 52. The jack press-fitting plate 52 has a grounding terminal 58a below the press-fitting hole 54, which projects from the lower surface thereof. The grounding terminal 58a is directly soldered to a grounding pattern formed on the back surface of the tuner board 42. (See FIG. 2).

After the tuner pack 40 is adjusted and inspected as a single unit, as shown in FIG. 2, the tuner pack 40 is in a vertical state with respect to the main board 62 arranged in parallel with the bottom surface of the chassis 64. Will be fixed in place. Then, in order to perform signal input / output between the main board 62 and the tuner board 42, the pins 48 of the connector 46 mounted on the tuner pack 40 are inserted into holes (not shown) formed in the main board 62. Be soldered. Further, in order to attach the tuner pack 40 to the main board 62, attachment pieces 58a and 58b formed on the first and second shield cases 50a and 50b are provided on both longitudinal ends of the tuner pack 40. . One attachment piece 58 a is formed at the end of the jack press-fitting plate 52. Each of the mounting pieces 58a and 58b is inserted into a square hole (not shown) formed in the main board 62, and is soldered to an earth pattern formed around the square hole. Furthermore, in the first shield case 50a,
A mounting hole 60 is formed, and the mounting hole 60 is used for screw fixing to the rear surface 66 of the chassis 64. The second shield case 50b is not always necessary.

As a result, the ground pattern formed on the tuner board 42 of the tuner pack 40 is set to the ground potential via the first shield case 50a and the chassis 64. In this way, the tuner pack 40 is attached to the main board 62 and is fixed to the rear surface 66 of the chassis 64 by screwing,
The jack opening of the antenna jack 20 mounted on the tuner pack 40 faces the predetermined position on the back surface 66 of the chassis 64. Back 66
Has a notch at a position facing the jack opening.

As described above, the first advantage of the tuner pack 40 equipped with the antenna jack 20 is that various adjustments for the front end, such as tracking adjustment, can be performed under substantially the same conditions as the actual usage conditions. is there.
That is, when performing tracking, the antenna plug is inserted into the antenna jack 20 mounted on the tuner pack 40, and the necessary input / output is connected to the connector 46. Then, a signal generator (not shown) oscillates a necessary reference frequency for tracking adjustment, and the capacitance of the capacitors provided in the antenna and the high-frequency tuning circuit constituting the high-frequency amplifier circuit 22 and the capacitance of the local oscillator circuit 26 are adjusted. , Will be adjusted so that predetermined tracking can be obtained. Alternatively, each of the above-mentioned capacitors is composed of a voltage-controlled variable capacitance capacitor, and the applied voltage for various predetermined frequencies is adjusted. At this time, the antenna input is not performed by using the pins formed on the substrate only for the adjustment such as the tracking adjustment, unlike the conventional case.
Since antenna input can be performed by the antenna jack 20 actually used in the market, more accurate tracking adjustment can be performed.

A further advantage of the tuner pack 40 is that unnecessary harmonic radiation can be effectively prevented.

That is, first, focusing on the signal line of the antenna input, both the front end circuit and the antenna jack 20 are mounted on the same board 42, and the signal terminal 20b of the antenna jack 20 is on the back surface of this board 42. It is directly soldered to the formed signal pattern. Therefore, since the signal line can be formed by using the pattern in the same substrate without being drawn by a wire as in the conventional case, the signal line can be set to the shortest.

Next, paying attention to the ground line of the antenna input, in this embodiment, this ground line can be made the shortest and its impedance can be minimized. That is, the grounding tubular body 20a of the antenna jack 20 is directly connected to the jack press-fitting plate 52 formed by extending a part of the first shield case 50a for setting the ground potential of the front end circuit. Further, a part of the jack press-fitting plate 52 is used as a ground terminal 58a, and the ground terminal 58a is used as the substrate 4
Soldered directly to the ground pattern of No.2.

Therefore, the grounding tubular body 20a of the antenna jack 20 immediately receives the front end circuit 2 at the entrance of the antenna input of the front end circuit 21.
Therefore, the potential is set to be substantially the same as the ground potential of 1. This action is ensured by directly connecting the ground terminal 58a of the jack press-fitting plate 52 into which the grounding tubular body 20a is press-fitted to the ground pattern of the tuner board 42 on which the front end circuit 21 is mounted. In this case, the ground pattern of the board 42 and the jack press-fitting plate 52 form a ground line. However, the ground pattern of the board 42 on which both the antenna jack 20 and the front end circuit 21 are mounted can be made sufficiently shorter than the conventional one. Further, since the jack press-fitting plate 52a can have a sufficiently large thickness as compared with the pattern thin film, the impedance in the ground line can be sufficiently reduced. Therefore, the antenna jack 2 is provided on the substrate 42.
Since 0 and the front end circuit 21 are both mounted, the distance of this ground line can be made sufficiently shorter than in the conventional case. In this way, the impedance of the ground line at the antenna input section can be made sufficiently low and the distance of the signal line can be shortened. Therefore, the output f0 oscillated by the local oscillation circuit 26 in the front end circuit 21 and 2fo, Unwanted harmonics such as 3fo can be sufficiently reduced from leaking outside from the signal line as unnecessary radiation.

Further, in the case of an on-vehicle radio receiver, the ground of the front end circuit 21 is finally connected to the chassis 64.
Will be set to the ground potential via. At this time, according to the present embodiment, the first shield case 50a mounted on the tuner pack 40 is replaced by the chassis 64
It is fixed to the back surface 66 of the same with screws. Therefore, the function of connecting the grounding tubular body 20a of the antenna jack 20 to the ground terminal of the front end circuit and the function of connecting the ground terminal of the front end circuit 21 to the chassis are provided at one location of the first shield case 50a. And the impedance on the ground line for setting the ground potential can be more effectively reduced. Also from this, the above-mentioned unnecessary radiation can be effectively reduced.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the present invention. In the above embodiment, on the substrate 42 of the tuner pack 40, in addition to the high frequency amplification circuit 22, the mixing circuit 24, and the local oscillation circuit 26 for forming the front end circuit 21, the FM intermediate frequency circuit 30 to the FM multiplex 36 are provided. Although the circuits up to and including the AM circuit 38 and the like are built in, the invention is not limited to this. As an effect of the present invention, at least adjustments for front end such as tracking adjustment can be made by the tuner device alone under the same conditions as actual use conditions, and further, local oscillation in the front end circuit 21 can be performed. The purpose is to prevent unnecessary radiation from the circuit 26. When configuring the front-end device, the components mounted on the substrate 42 may simply include the circuits 22, 24, and 26 configuring the antenna jack 20 and the front-end circuit 21.

The jack press-fitting plate 52 for press-fitting and supporting the antenna jack 20 on the tuner board 42 is
First shield case 5 surrounding the front end circuit 21
It is not limited to the one formed by extending a part of 0a. Figure 6
Shows an example in which the jack press-fitting plate 52 is formed separately from the first shield case 50a. The jack press-fitting plate 52 is used for the first shield case 50a.
Has a mounting position 52a at a position flush with the side surface fixed to the chassis back surface 66. The mounting plate 52a is provided with a mounting hole 52b for screwing the chassis 64.
Are formed.

In the embodiment shown in FIG. 6, although the number of parts of the metal fitting is increased, the impedance of the ground line of the antenna jack 20 is reduced and the impedance is reduced as in the above embodiment.
The ground line can be made sufficiently shorter than before.
Therefore, even in the embodiment shown in FIG. 6, it is possible to effectively reduce the unwanted radiation from the local oscillation circuit 26.

FIG. 7 shows a modification of the tuner board 42. In the embodiment shown in FIG. 7, the tuner board 42 is composed of two boards, a first circuit board 120 for the front end circuit 21 and a second circuit board 130 on which other circuits are mounted. . The first and second circuit boards 120 and 130 are initially connected as one board from the joining pieces 120a and 130a provided on the opposite sides thereof, and can be manually cut into two boards. ing.

Components for the front end circuit 21 shown in FIG. 3 are mounted on the first circuit board 120, and a first shield case 122 is provided to cover these components. Further, a first connector 124 for inputting / outputting a signal to / from the main board 62 is mounted on the first circuit board 120. First shield case 122
Both ends of the are formed as attachment pieces 122a and 122b protruding from the end portion of the first circuit board 120. This each mounting piece 1
22a, 122b and the pins of the first connector 124 allow the first circuit board 120 to be vertically mounted on the main board 62.

The second circuit board 130 mounts components for each of the circuits 30 to 38 other than the front end circuit 21 shown in FIG. 3, and the second shield case 1 surrounding these components.
32 is provided. In addition, the second circuit board 13
Similarly, 0 also has a second connector 134 for inputting / outputting signals to / from the main board 62. Second
The shield case 132 mainly includes the second circuit board 130.
Functions as a mounting bracket for vertically leaning on the main board 62, and mounting pieces 132a and 132b to be inserted into the main board 62 are formed at both ends thereof.

Further, the first and second circuit boards 120, 13
A parallel line cable 138, for example, is connected between the two substrates in order to perform signal input / output between 0s. The first and second circuit boards 120 and 130 are connected and integrated until the tracking adjustments of AM and FM are completed, and then divided into two before being mounted on the main board 62. Therefore, the step of automatically inserting the components into the first and second circuit boards 120 and 130 and the subsequent step of automatic soldering can be handled as one circuit board. Further, since the antenna jack 20 is press-fitted and supported by the jack press-fitting plate on the single board in which the first and second circuit boards 120 and 130 are integrated, as in the above-described embodiment, it is possible to determine the actual use state. Tracking adjustment can be performed under the same conditions.

FIG. 8 shows a layout example in which the first and second circuit boards 120, 120 divided into two are mounted on the main board 62 arranged in the chassis 64. The device shown in FIG. 8 shows a vehicle-mounted radio receiver equipped with a cassette tape player 140. The first circuit board 120 is arranged such that the antenna jack 20 is located at the left end position when viewed from the rear surface 66 side of the chassis 64. The first and second circuit boards 120 and 130 are arranged between the tape player 140 and the chassis back surface 66. According to such a layout, the tape player 140 is shifted to the left side in FIG. 8 as compared with the case where the first and second circuit boards 120 and 130 are configured by one board as shown by the chain line in FIG. Can be placed in position.
As a result, the display means, such as the LCD 144, arranged on the front side of the apparatus can be arranged in a relatively wide area on the right side of the front side of the apparatus in FIG. If the first and second circuit boards 120 and 130 are
When configured with a single board, the circuit board 1 shown by the chain line
The tape player 140 must be arranged in a position shifted to the right in FIG. 8 so that the tape player 140 does not interfere with the tape player 140.

Here, in the tape player 140, in order to make the depth dimension of the player shorter than the standardized depth dimension L of the apparatus body, the motor 142 is projected from the side surface of the player 140 body, for example, the right side surface. It is usually provided at a position. The presence of the motor 142 also limits the amount by which the player 140 is shifted to the right. Therefore, in this case, the areas left on the left and right sides of the tape player 140 are reduced, and the width of the LCD 144 has to be shortened.

In the present embodiment, the LCD 144 can have a relatively large screen within the standardized lateral width W of the device, and the flexibility of the layout on the front side of the device can be expanded. In FIG. 8, the power IC circuit 146 is arranged on the right side of the tape player, and the connector 148 is arranged on the back side thereof. Since the tape player 140 can be shifted to the left side in FIG. 8, the power I
This has the effect of increasing the degree of freedom of the installation area of the C circuit section 146.

Further, in order to dispose the first circuit board 120 at a position shifted to the left side of the apparatus main body shown in FIG. 8, as shown in FIG. 7, it is a part of the first circuit board 120. The notch 121 may be provided in a region of the antenna jack 20 that faces the ground tubular body 20a.

As a result, as shown in FIG. 8, the pattern surface side of the first circuit board 120 and the antenna jack 20 are connected.
The peripheral surface of the grounding tubular body 20a can be made substantially flush. Therefore, the height H from the first circuit board 120 to the top of the grounding tubular body 20a can be further reduced. By using the circuit component 44 having a height within the height H from the board 120, the first circuit board 120 can be laid out at a position shifted to the left side of the device.

Next, circuits mounted on the tuner board 42 shown in FIG. 3 and the main board 62 shown in FIG. 2 will be described with reference to FIG.

The front end circuit 21 mounted on the tuner board 42 is the high frequency amplifier circuit 2 as described above.
2. It has a mixing circuit 24 and a local oscillation circuit 26. The high frequency amplifier circuit 22 is roughly classified into an antenna tuning circuit 150.
And RF tuning circuit 154. The antenna tuning circuit 150, the RF tuning circuit 154, and the local oscillation circuit 26 have built-in first to third variable capacitance diodes 152, 156, and 158 whose capacitance values are varied by an applied voltage. In addition, the connector 46 mounted on the tuner board 42 includes the first to third variable capacitance diodes 15
First to third voltage application terminals 160, 162, 164 connected to 2, 156, 158 are provided. Further, the connector 46 is provided with an output terminal 166 of the local oscillation circuit 26.

Further, on the tuner substrate 42,
Each circuit 30 other than the front end circuit 21 shown in FIG.
Besides 38, a memory element, for example, an electrically rewritable EEPROM 170 and a constant voltage power supply circuit 172 are mounted. The EEPROM 170 stores, for example, 8-bit data as tracking data that determines each applied voltage to the first and second variable capacitance diodes 152 and 156 when the tracking is optimally performed at a plurality of frequencies. The constant voltage power supply circuit 172 is for setting a reference potential for the voltage applied to the first and second variable capacitance diodes 152, 156, and in this embodiment, 8.8 V is the reference potential. For a certain frequency f1, the 8-bit tracking data for the first and second variable capacitance diodes 152 and 156 is set to A1, respectively.
Assuming B1, the applied voltage to the first variable capacitance diode 152 is 8.8 × A1 / 258a (V), and the applied voltage to the second variable capacitance diode 156 is 8.8 × B1 / 258a (V). .

The relationship between the voltage applied to the variable capacitance diode and the tuning frequency is as shown in FIG. In FIG. 10, for example, voltages Vmin to Vmax applied to the diode when tracking adjustment is performed for each of a plurality of frequencies up to frequencies Fmin to Fmax are obtained. The tracking data stored in the EEPROM 170 includes the diodes 152,
Every 156 becomes 8-bit data corresponding to the applied voltage of Vmix to Vmax.

The reason why the memory element mounted on the tuner board 42 is the rewritable EEPROM 170 is that the memory is data other than the tracking data, and the stored information that needs to be rewritten in the on-vehicle radio receiver. Because it remembers. When storing data for digital tuning, the EEPROM 170 is used as the memory element so that preset data of a desired reception frequency can be rewritten.

Further, the connector 46 mounted on the tuner board 42 is provided with an input / output terminal 174 for the EEPROM 170 and an output terminal 176 of the constant voltage power supply circuit 172.

On the other hand, on the main board 62, digital
A microcomputer 180 that controls the tuning system is provided. When the arbitrary frequency F shown in FIG. 9 is selected, the microcomputer 180 has V3 and V4 corresponding to the frequencies F3 and F4 before and after that.
The tracking data relating to the applied voltage V is read from the EEPROM 170, and the data for the applied voltage V for the arbitrary frequency F is obtained by interpolation calculation. Then, the microcomputer 180 converts the voltage determined by the above formula based on the obtained data into the first and second low pass filters 182 and 184 and the first and second voltage application terminals 16
It is applied to the variable capacitance diodes 152 and 156 of the antenna tuning circuit 150 and the RF tuning circuit 154, respectively, via 0 and 162.

Further, this microcomputer 180
Incorporates a phase locked loop (PLL) 188. The PLL 188 sets the oscillation frequency of the local oscillation circuit 26 to, for example, the reception frequency fr and the intermediate frequency fi.
It locks to the sum frequency of. This PLL1
The output of 88 is applied to the third variable capacitance diode 158 of the local oscillation circuit 26 via the third low-pass filter 186 and the voltage application terminal 164.

On the tuner board 42 shown in FIG. 9, in addition to the front end circuit 21 and the AM circuit 38, E
The tuner pack 40 including the EPROM 170 and the constant voltage power supply circuit 172 is separated from the main board 62, and tracking adjustment is performed in a single state. Therefore, during the tracking adjustment, the main substrate 6
Microcomputer 180 mounted on the second, first to
This is performed using a tracking adjustment device having the functions of the third low pass filters 182 to 188. After performing the tracking adjustment using this tracking adjustment device, the tracking data corresponding to the proper applied voltage to the first and second variable capacitance diodes 152 and 516 of the antenna tuning circuit 150 and the RF tuning circuit 154 is the tuner data. It is stored in the EEPROM 170 in the pack 40. This proper applied voltage is a reference potential (for example, 8.8 V) of the constant voltage power supply circuit 172 mounted in the tuner pack 40.
Has been detected using.

By the way, as described above, the voltage applied to the first and second variable capacitance diodes 152 and 156 is determined by the above-mentioned equations, and the applied voltage is the reference potential of the constant voltage power supply circuit 172, respectively. Has been determined using. If this reference potential is set using the reference potential of the constant voltage power supply circuit outside the tuner pack 40, for example, in the tracking adjusting device, the following problems occur. That is, when the tuner pack 40 is incorporated in the radio receiver, the reference potential is not set by the constant voltage power supply circuit in the tracking adjustment device, but, for example, the constant voltage power supply circuit is provided on the main circuit 62. And the reference potential is used. In this case, if there is a slight difference in the reference potential between the constant voltage power supply circuit of the tracking adjustment device and the constant voltage power supply circuit mounted on the main board, the first and first values determined by the above equations are used. The voltage applied to the second variable-capacitance diodes 150 and 156 is different from the voltage applied during tracking adjustment.

According to this embodiment, the reference potential in the tracking adjustment and the reference potential in the actual use state are both set by the reference potential in the constant voltage power supply circuit 172 in the tuner pack 40. It is possible to prevent the applied voltage from being different during adjustment and during actual use condition tuning.
If there is a difference in the applied voltage, so-called misalignment occurs, and it becomes necessary to perform fine adjustment again after mounting the tuner pack 40 and the main board 62 in the radio receiver main body. In the present embodiment, due to the above-mentioned structure, once the tuner pack 40 is once adjusted for tracking, there is no need for readjustment when it is incorporated into the radio receiver body.

The shift in tuning when the reference potential shifts is remarkable especially in the case of AM. This is because in the case of AM, the Q of each variable capacitance diode of the antenna and the RF tuning circuit is
Is steep, and the sensitivity is significantly reduced by a slight shift in the applied voltage. Therefore, although not shown in FIG. 9, the microcomputer 1 is mounted on the main substrate 62.
80 may be configured to apply a voltage also to the variable capacitance diode of the high frequency amplifier circuit of the AM circuit 38 in the tuner substrate 42. In this case, the tracking data for AM tuning may also be stored in the EEPROM 170 mounted on the tuner board 42.

When the embodiment of FIG. 9 is applied to a tuner device having a structure in which it can be divided into first and second circuit boards 120 and 130 as shown in FIGS.
70 and the constant voltage power supply circuit 172 are mounted on the second circuit board 130, respectively. Also, the terminals 160 to 166 and 1
74 and 176 are the first and second connectors 124 and 134.
All you have to do is to allocate them to.

Further, when the memory for storing the tracking data and the constant voltage power supply circuit 172 for setting the reference potential of the voltage applied to the tuning variable capacitance diode are mounted on the tuner board 42 or the second circuit board 130, it is not always necessary. Connect the antenna jack 20 to the tuner board 42 or the first
The circuit board 120 may not be mounted. Even in this case, the accuracy of tracking adjustment is further improved at least as compared with the case where the reference potential differs at the time of adjustment and in the actual use state.

[0064]

As described above, according to the present invention, unnecessary harmonic radiation from the local oscillator in the front end circuit is effectively prevented, and the front end device alone or the tuner device is used. By itself, tracking adjustment can be performed under almost the same conditions as the actual usage conditions.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a front end device to which the present invention is applied.

FIG. 2 is a schematic explanatory view showing an arrangement of the front end device shown in FIG. 1 in a chassis.

3 is a block diagram of a circuit mounted in the front end device shown in FIG. 1. FIG.

FIG. 4 is a schematic perspective view showing a conventional structure for connecting a front end circuit and an antenna jack using a coaxial cable.

FIG. 5 is a schematic perspective view showing a conventional structure in which an antenna jack is mounted on a substrate.

FIG. 6 is a schematic perspective view showing a modified example in which the shield case and the jack mounting plate are separate bodies.

FIG. 7 is a schematic plan view showing a state where the tuner board is divided into first and second circuit boards.

FIG. 8 is a schematic plan view showing a layout example in which first and second circuit boards are arranged at different positions in the chassis.

FIG. 9 is a block diagram showing a state in which a memory and a constant voltage power supply circuit are mounted on the tuner board side, and a microcomputer is mounted on the main circuit board side.

FIG. 10 is a characteristic diagram showing a relationship between a voltage applied to a tuning variable capacitance diode and a frequency.

[Explanation of symbols]

 20 antenna jack 20a grounding tubular body 20b signal terminal 21 front end circuit 22 high frequency amplification circuit 24 mixing circuit 26 local oscillation circuit 40 tuner device 42 tuner circuit board 44 tuner circuit component 46 connector 50a shield case 52 jack mounting plate 62 main board 64 chassis 120 first board 124 first connector 130 second board 134 second connector 138 cable 140 player 152, 156, 158 variable capacitance diode 170 memory 172 constant voltage power supply 180 microcomputer

Claims (12)

[Claims] 1. A tuner device for converting an antenna input signal into an audio signal, a circuit board having an earth pattern and various signal patterns formed thereon, and a tuner circuit mounted on the circuit board and connected to the signal and earth pattern. Parts, a connector for signal input / output mounted on the tuner circuit board, fixed to the tuner circuit board by being connected to the ground pattern, and among the tuner circuit parts, a high-frequency amplifier circuit, a mixing circuit, and a local portion An antenna of the tuner circuit board, which includes a shield case that encloses an FM wave front-end circuit component that constitutes an oscillation circuit, a cylindrical body for grounding, and a signal terminal insulated from the cylindrical body for grounding. An antenna jack connected to the signal pattern for input, and extending a part of the shield case And a jack mounting plate configured to press-fit and support the grounding tubular body of the antenna jack. 2. The tuner circuit component mounted on the tuner circuit board according to claim 1, wherein the tuner circuit component includes a tuner circuit component for FM waves and AM waves, and the tuner circuit substrate includes the antenna jack and the front end. A first circuit board on which the circuit component and the shield case are mounted, and a second circuit substrate on which the tuner circuit component for the FM wave and the AM wave other than the front end circuit component is mounted, and a cutting portion that can be cut. The connector mounted on the tuner circuit board includes a first connector mounted on the first circuit board and a second connector mounted on the second circuit board, A tuner device comprising a cable for inputting and outputting a signal between the first and second circuit boards. 3. The front end circuit component according to claim 1 or 2, wherein the front end circuit component includes a variable capacitance diode for FM wave tuning, the capacitance value of which varies depending on an applied voltage, and the tuner circuit component for AM wave has a capacitance depending on an applied voltage. The tuner circuit board includes a variable capacitance diode for tuning an AM wave whose value changes, and tracking data corresponding to a voltage applied to each variable capacitance diode for tuning the FM wave and the AM wave for each of a plurality of frequencies. Memory to store,
A constant voltage power supply circuit that sets a reference voltage of a voltage applied to each of the variable capacitors is mounted, and the connector has an input terminal for a voltage applied to each of the variable capacitors and a data input / output to / from the memory. A tuner device comprising a terminal and a voltage output terminal of the constant voltage power supply circuit. 4. The tuner device according to claim 3, wherein the memory has a memory area for rewritably storing various data necessary for digital tuning. 5. A chassis set to a potential, a main circuit board horizontally arranged in the chassis, and a main circuit board mounted on the main circuit board.
And a tuner circuit board on which an earth pattern and various signal patterns are formed, and the tuner apparatus is mounted on the tuner circuit board and connected to the signal and earth pattern. Tuner circuit component, and an FM wave front-end circuit that is connected to the ground pattern and fixed to the tuner circuit board to form a high-frequency amplifier circuit, a mixing circuit, and a local oscillator circuit of the tuner circuit component. A shield case that encloses the parts, and is mounted on the tuner circuit board outside the shield case, and has a grounding tubular body and a signal terminal insulated from the grounding tubular body, and the signal terminal is the An antenna jack connected to the signal pattern for antenna input on the tuner circuit board, and the shield case A jack mounting plate that is configured by extending a part and press-fits and supports the grounding tubular body of the antenna jack; and signal patterns of the tuner circuit board and the main circuit board that are mounted on the tuner circuit board. A connector for supporting the tuner circuit board vertically to the main circuit board by connecting to the shield circuit, and the shield case is fastened and fixed at one end side in the width direction of the rear surface of the chassis, An in-vehicle radio receiving device, wherein a rear surface of the chassis has a cutout portion that exposes the antenna jack to the outside at the one end. 6. The tuner circuit component according to claim 5, wherein the tuner circuit component mounted on the tuner circuit substrate includes a tuner circuit component for FM wave and AM wave tuning, and the tuner circuit substrate includes the antenna jack and the front end. A cutting section that can be cut into a first circuit board on which circuit components and the shield case are mounted and a second circuit board on which the tuner circuit components for FM and AM wave tuning other than the front end circuit components are mounted. And the connector mounted on the tuner circuit board includes a first connector mounted on the first circuit board and a second connector mounted on the second circuit board. A signal input / output cable between the first and second circuit boards is provided, and the first and second circuit boards are cut by the cutting portion after tracking adjustment. Has been, said on the main circuit different position on a first-vehicle radio receiver apparatus characterized by being vertically supported respectively to the main circuit board by the second connector. 7. The player for cassette tapes, compact discs, etc. fixed to the front surface of the chassis above the main circuit board in the chassis according to claim 6, The in-vehicle radio receiver, wherein the second circuit board is supported on the main circuit board in a region between the player and the rear surface of the chassis. 8. The front-end circuit component according to claim 5, wherein the front-end circuit component includes a variable-capacitance diode for FM wave tuning, the capacitance value of which varies depending on an applied voltage. The tuner circuit board includes a variable capacitance diode for AM wave tuning, the capacitance value of which varies depending on a voltage, and a plurality of types of tracking data corresponding to applied voltages to the variable capacitance diodes for FM wave and AM wave tuning. Memory to store for each frequency,
A constant voltage power supply circuit that sets a reference voltage of a voltage applied to each of the variable capacitors is mounted, and the connector has an input terminal for a voltage applied to each of the variable capacitors and a data input / output to / from the memory. A control circuit for controlling digital tuning, the control circuit including a terminal and a voltage output terminal of the constant voltage power supply circuit; An in-vehicle radio receiving device, characterized in that a voltage applied to a capacitance diode is calculated based on the tracking data in the memory, and the voltage from the constant voltage power supply circuit is set as a reference. 9. The in-vehicle radio receiver according to claim 8, wherein the memory has a memory area for rewritably storing various data necessary for digital tuning. 10. A front end device for converting an antenna input signal of an FM wave into an intermediate frequency signal, a circuit board having a ground pattern and various signal patterns formed thereon, and the signal and ground mounted on the circuit board. Front-end circuit parts connected to the pattern and constituting a high-frequency amplifier circuit, a mixing circuit, and a local oscillation circuit; and a connector for signal input / output to / from each circuit mounted on the circuit board, and connected to the earth pattern. Fixed to the circuit board and surrounding the front end circuit component, a grounding tubular body and a signal terminal insulated from the grounding tubular body, the signal terminal being the antenna input of the circuit board. And an antenna jack connected to the signal pattern for A jack mounting plate for press-fitting and supporting the grounding tubular body of the antenna jack, and a front end device. 11. The circuit board according to claim 10, wherein the circuit board has a cutout portion that is formed by cutting out a region of the antenna jack that faces the grounding tubular body, and the antenna jack includes the grounding tubular body. Is mounted on the circuit board so that a part of it is located within the range of the thickness of the circuit board, and all of the front end circuit components are elevated from the surface of the circuit board to the top of the grounding tubular body. A front-end device having a height of a component that falls within a height range. 12. A front end device for converting an antenna input signal of an FM wave into an intermediate frequency signal, a circuit board having a ground pattern and various signal patterns formed thereon, and the signal and ground mounted on the circuit board. Front-end circuit parts connected to the pattern and constituting a high-frequency amplifier circuit, a mixing circuit, and a local oscillation circuit; and a connector for signal input / output to / from each circuit mounted on the circuit board, and connected to the earth pattern. Fixed to the circuit board and surrounding the front end circuit component, a grounding tubular body and a signal terminal insulated from the grounding tubular body, the signal terminal being the antenna input of the circuit board. Antenna jack connected to the signal pattern for the, and to the circuit board connected to the ground pattern A jack mounting plate that is fixed and press-fits and supports the grounding tubular body of the antenna jack; the shield case is provided on a side surface facing a chassis of a device in which the front end device is mounted. Has a first hole for screw fixing to the chassis, the jack mounting plate has a mounting surface flush with the side surface of the shield case, and is screwed to the chassis on the mounting surface. A front-end device, characterized in that a second hole is provided.