JPH0735519Y2 - Car audio system - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an in-vehicle audio system, in particular, an audio source device having an electronic volume at an output stage,
The present invention relates to an in-vehicle audio system in which a graphic equalizer device with a spectrum analyzer is connected in tandem in the front and rear.

[Conventional technology]

Generally, in a car audio system, a plurality of audio source devices are connected in tandem in the front and rear, and a power amplifier is connected in the last stage. When connecting a single graphic equalizer device with a spectrum analyzer to the system, it is inserted between the last stage of the audio source device and the power amplifier.

FIG. 10 shows a cassette deck (hereinafter simply referred to as "deck") 10 and a CD player (hereinafter simply referred to as "player")
After the 30s are connected in series, they are divided into two systems, the front side (F) and the rear side (R), and the front side is a power amplifier.
A system in which a power amplifier 99 is directly connected to the power amplifier 50 and a rear side of the power amplifier 99 is connected via a graphic equalizer with a spectrum analyzer (hereinafter, simply abbreviated as “glyco”) 60.

When ACC power is supplied to each set and the cassette is inserted into the deck 10 with the power switch of the player 30 turned on, the micro control (hereinafter simply referred to as " (Abbreviated as "microcomputer") 14 controls the loading mechanism unit 16 to load the cassette, and then reproduces the cassette.
Play control is performed on the mechanical section 18 to play the tape.
At this time, the switch SW _D is switched to the A side and the H-level P-CON signal is output to the subsequent stage side.

The microcomputer 34 of the player 30, which receives the P-CON signal, switches the switch SW _P to the B side and outputs the P-CON signal to the subsequent stage.

Switch SW for L and R 2ch audio signals accompanying tape playback
_It is input to the electronic potentiometer 40 via _D , the electronic potentiometer 20, and the switch SW _P , where the volume is adjusted, the front and rear are separated, and the fader between the front and rear is adjusted. It is output to 50 and the rear side is output to the glyco 60. The power amplifier 50, which receives the P-CON signal, is activated and amplifies the power of the front audio signal to output the front speaker.
The FL and front R side speaker FR are driven.

Further, the microcomputer 62 of the glyco 60 which receives the P-CON signal supplies power to the respective parts in the set to activate them.
After the characteristics of the rear side audio signal are changed according to the user's operation for changing the characteristics of the glyco in the glyco section 64 of the glyco 60 (here, L and R are assumed to have the same characteristics),
Output to the power amplifier 99.

The P-CON signal input to the Glyco 60 is the power amplifier 99
The power amplifier 99 is also activated by the input of the P-CON signal to be in an operating state, amplifies the power of the rear audio signal, and drives the rear L speaker RL and the rear speaker RR.

In the glico 60, a spectrum analyzer unit 66 provided on the output side of the graphic unit 64 displays a spectrum spectrum in which the audio band is divided into three bands. First, L and R are mixed in the mixing amplifier 68, and B
After the low-frequency, mid-range, and high-frequency components are extracted by PF70-74, they are DC-detected by detectors 76-80, respectively. Then, A / D converters 82 to 86 perform A / D conversion for each band. The outputs of the three A / D converters 82 to 86 are input to the microcomputer 62, and the logarithm of the ratio with the reference level data RD (rounded to an integer) is taken. And from these logarithmic values, dB for each band
Unit display data is created and the corresponding LCD driver 88
Output to ~ 92.

The LCD drivers 88 to 92 are LCDs each composed of a plurality of display elements.
The display units 94 to 98 are driven to display the spectrum analyzer.

If the variable gain range of the graphic section 64 is set to ± 12 dB, when the audio signal output from the cassette playback / mechanical section 18 is attenuated by -20 dB and input to the graphic section 64, the spectrum analyzer display will be at an almost appropriate level. It is supposed to be done.

The electronic volume 20 of the deck 10 is for volume adjustment, and the attenuation amount is varied within a range of, for example, 0 to -60 dB by the volume variation control of the microcomputer 14 according to the volume variation operation on the operation unit 22. Further, the electronic volume 40 of the player 30 is, as shown in FIG. 11, an electronic volume for volume 40A provided on the front side and an output side of the electronic volume for volume 40A divided into two systems, and a front fader provided for each system. The electronic volume 40B for the rear side and the electronic volume 40C for the fader on the rear side are provided, and the volume variation control of the microcomputer 34 according to the volume variation operation in the operation unit 42 allows the attenuation amount in the volume electronic volume 40A to fall within the range of 0 to −60 dB Or the fader variable control according to the fader variable operation in the operation unit 42 is used to vary the attenuation amount in the front side or rear side fader electronic volume 40B or 40C within the range of 0 to -30 dB.

However, when the deck 10 and the player 30 are connected back and forth, the user usually fixes the volume of the deck 10 on the preceding stage side to the maximum volume of the attenuation amount of 0 dB, and performs the volume adjustment and the fader adjustment on the player 30 side.

When it is desired to listen to the CD instead of the tape, when the CD is inserted into the player 30, the microcomputer 34 controls the loading mechanism section 36 to load the CD based on the insertion detection signal input from the CD insertion detection section 32. Then, when the PLAY key of the operation unit 42 is turned on, the microcomputer 34 controls the CD reproduction / mechanical unit 38 to play the CD, switches the switch SW _P to the A side, and outputs the H-level RST signal to the preceding stage. Then, P to the rear side
-Continue the CON signal output.

This switches the audio signal reproduced from the CD.
It is input to the electronic volume 40 via SW _P , where volume adjustment and fader adjustment are performed, and then output to the power amplifier 50 and the glyco 60, so that the CD sound is output this time.

In the spectrum analyzer 66 of the glico 60, spectrum analyzer display of the audio signal relating to the CD is performed.

[Problems to be solved by the device]

However, in the above-described conventional system, when the volume of the player 30 is changed or the fader is changed to lower the level of the rear side with respect to the front side, the signal level input to the spectrum analyzer 66 of the glyco 60 is changed. Therefore, the signal level becomes too high and the LCD display 94 of the spectrum analyzer 66 is
Almost all the display elements of ~ 98 are turned on, or almost all the display elements are turned off because the signal level becomes too low, and it is possible to compare the level by band from the spectrum display. There is a drawback in that it becomes difficult and it becomes difficult to adjust to the desired glyco characteristics.

In consideration of the above-mentioned problems of the prior art, the present invention ensures that the spectrum analyzer display is always displayed at an appropriate level even if a variable operation related to the volume or the volume such as the fader is performed by the audio source device connected in the preceding stage of the glyco. The purpose is to provide an in-vehicle audio system.

[Means for Solving the Problems]

In the in-vehicle audio system of the present invention, an audio source device and a graphic equalizer device are connected in tandem in a front and rear direction, and the audio source device has an electronic volume provided in an output stage, an operating means for performing a variable operation related to the volume, and an operating means. The graphic equalizer device is equipped with a spectrum analyzer means for displaying the level of each audio signal band by spectrum analyzer. In the audio equipment, the control means of the audio source equipment outputs the data related to the volume to the graphic equalizer equipment in the subsequent stage, and the spectrum analyzer means of the graphic equalizer equipment changes the sensitivity of the spectrum analyzer display based on the data related to the volume. By installing the variable sensitivity means it is characterized.

〔Example〕

 One embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram showing an in-vehicle audio system according to the present invention.

The same components as those in FIG. 10 are designated by the same reference numerals.

The operation part 22 of the deck 10A is provided with a volume up key and a volume down key.
Rewrites the volume data VD in RAM, outputs a control signal including the volume data VD to the electronic volume 20, and performs volume control.

The control signal output from the microcomputer 14 to the electronic volume 20 includes data DATA including a volume code and volume data VD, a clock CLK, and a strobe STR.
On the other hand, when the volume variable control is performed, the strobe signal rises first, and the data DATA is serially output in synchronization with the clock CLK. When the output of data DATA ends, strobe STR falls.

When the volume code is input, the electronic volume 20 changes the attenuation amount according to the volume data VD that follows.

The control signal to the electronic volume 20 is also output to the control signal output terminal of the deck 10A, but this control signal output terminal is not connected to the subsequent set. The operation unit 22 is also provided with an eject key. The other components of the deck 10A are constructed exactly as in FIG.

The operation unit 42 of the player 30A is provided with a volume up key, a volume down key, an F side fader key, and an R side fader key, and the microcomputer 34 controls the volume data VD of RAM or the front side fader data FFD or the rear side according to the user's operation. Rewrite the fader data RFD, these VD, FFD,
A control signal including RFD is output to the electronic volume 40 to perform volume variable control and fader variable control.

The control signal output from the microcomputer 34 to the electronic volume 40 also includes data DATA, clock CLK, and strobe STR.
When performing variable control of volume, data DATA includes volume code and volume data VD, and when performing front side fader variable control, data DATA consists of front side fader code and front side fader data FFD, and rear side fader control is performed. When performed, the data DATA consists of the rear side fader code and the rear side fader data RFD.

When the volume code is input, the electronic volume 40 changes the attenuation amount of the volume electronic volume 40A based on the volume data VD that follows, and when the front side fader code is input, the electronic volume 40B for the front side fader based on the front side fader data FFD that follows. The rear fader data RFD continues when the rear fader code is input by changing the attenuation amount of
The amount of attenuation of the rear fader electronic volume 40C is changed based on.

The control signal to the electronic potentiometer 40 is also output to the control signal output terminal of the plate 30A, and the graphic signal is output via the connection cord.
It is input to the control signal input terminal of 60A.

The operation unit 42 is also provided with a PLAY key, a STOP key, and an eject key. The other components of the player 30A are the tenth
The configuration is exactly the same as the figure.

The microcomputer 62A of the glico 60A inputs the data from the A / D converters 82 to 86 and also the control signal for the electronic volume 40 sent from the plate 30A side through the control signal input terminal.

A mode switch (dip switch) 63 is connected to the microcomputer 62A, and there is a normal mode (N; there is no electronic volume in the front set) and a front mode (F; there is an electronic volume that allows volume and fader adjustment in the front set). , Connected to the front side), rear mode (R; there is an electronic volume that can adjust the volume and fader in the front stage set,
Connected to the rear side), volume mode (V; there is an electronic volume that can adjust the volume in the previous stage set) mode signal is input.

The microcomputer 62A consists of a CPU, ROM, and RAM that are connected to the bus.
Based on a predetermined program stored in M, spectrum analyzer display control processing including sensitivity variable processing is executed.

The other components of the Glyco 60A and the other components of the system are configured in exactly the same way as in FIG.

Next, the operation of this embodiment will be described with reference to the flow charts of FIGS. 2 to 4 show the operation of the microcomputer 14 of the deck 10A, FIGS. 5 to 7 show the operation of the microcomputer 34 of the plate 30A, and FIGS. 8 and 9 show the microcomputer of the glyco 60A. The operation of the 62A is shown.

It is assumed that the mode selector switch 63 is switched to the rear mode (R) (note that when it is connected to the front side, it is switched to the front mode, and when the electronic volume of the preceding stage set can adjust only the volume, it is switched to the volume mode, Switch to normal mode when there is no electronic volume).

The ACC power supply is turned off in advance, and the VD of the RAM of the microcomputer 14 is -6.
(DB), VD of the RAM of the microcomputer 34 = -18 (dB), FFD = 0
(DB), RFD = -20 (dB), and F = -20. Further, the deck 10A and the player 30A are in a state in which the cassette and the CD have been taken out.

When the ACC power is turned on, the microcomputer 14 of the deck 10A performs predetermined initialization processing to clear the graphs D, E and F, and sends a control signal including the volume code and volume data VD to the electronic volume 20.
And the volume (attenuation amount for the signal) is set to −6 dB (step 100 in FIG. 2).

Then, it is determined whether or not a cassette has already been set in the cassette reproduction / mechanical unit 18 (step 102) and whether or not an insertion detection signal is input from the cassette insertion detection unit 12 (step 10).
4. Whether or not the P-CON signal is input from the preceding stage side (step 106) and whether or not the P-CON signal input is stopped (step 106)
108), whether or not the RST signal is input from the subsequent stage (step 200 in FIG. 3), whether or not the RST signal input is stopped (step 202), and whether the eject key, volume up key, or volume down key is turned on. Repeat the judgment of whether or not (20
4, steps 300 and 302 in FIG. 4).

Also, when the ACC power is turned on, the Glyco 60A microcomputer 62A
Checks the setting mode with the mode changeover switch 63 (step 700 in FIG. 8), and since it is the rear mode here, VD is input by the control signal from the player 30A (step 702).

When the power switch of the plate 30A is turned on, the microcomputer 34
Performs a predetermined initialization process, clears the flags P, Q, R, C, outputs a control signal including a volume code and volume data VD to the electronic volume 40, and performs volume variable control on the volume electronic volume 40A. -18 dB. Subsequently, a control signal including the front side fader code and front side fader data FFD is output to the electronic volume 40, and the fader variable control for the front side fader electronic volume 40B is performed to 0 dB, the rear side fader code and the rear side fader code. Electronic volume 40 control signal including fader data RFD
Output to the rear side fader electronic volume control 40C to adjust the level to -20 dB (step 400 in FIG. 5).

Then, it is determined whether or not a CD is already set in the CD playback / mechanical unit 38 (step 402), whether or not an insertion detection signal is input from the CD insertion detection unit 32 (step 404), and whether or not the PLAY key is turned on. Or (step 406), P-CON from the front side
Whether the signal is input (step 408), whether the P-CON signal input is stopped (step 410), whether the RST signal is input from the subsequent stage (step 500 in FIG. 6), RST signal input Stop (step 502) and whether the STOP key or eject key is turned on (step 50).
4, 506), the volume up key, the volume down key, the F side fader key, and the R side fader key are repeatedly turned on (steps 600 to 606 in FIG. 7).

At the time of initial setting for the electronic volume 40, control signals relating to the volume and the fader are also output to the subsequent glyco 60A.

When the microcomputer 62A of the glico 60A first inputs VD by the control signal, it determines YES in step 702 of FIG. 8 and rewrites VD 'with the input VD (step 704). Next, when FFD is input, it is ignored, and when RFD is input, it is set to RFD '(steps 706 and 708).

Then,-(VD '+ RFD' + 20) is calculated and the correction data S
It is set as D (step 709). In the present case, SD = 18 (dB). Subsequently, the microcomputer 62A has a P-CON signal input (step 710).

When the user inserts the cassette into the deck 10A, the loading mechanism unit 16 is controlled based on the insertion detection signal input from the cassette insertion detection unit 12 to load the cassette (steps 104 and 110 in FIG. 2). Next, after confirming that the cassette has been set in the cassette playback / mechanical unit 18, PLAY control is performed to play the tape (step
102, 112).

At this time, the switch SW _D is switched to the A side, the H-level P-CON signal is output to the rear stage side, and the H-level RST signal is output to the front stage side (steps 114 and 11).
6). Then, the flag D is set and the flag E is cleared (step 118).

The audio signal reproduced from the tape is input to the electronic volume 20 via the switch SW _D , adjusted to a volume of -6 dB, and then output to the player 30A. To maximize the volume, first turn on the volume up key once
14 is YES in step 300 of FIG. 4, VD is increased by 2 to -4, and a control signal including this VD is output to the electronic volume 20 to set the volume to -4 dB (step 304,
306).

Similarly, when the volume up key is turned on twice, the maximum volume level becomes 0 dB.

The microcomputer 34 of the player 30A that receives the P-CON signal is
When YES is determined in step 408 of the figure, the switch SW _P is switched to the B side, and the H-level P-CON signal is output to the power amplifier 50 and the glyco 60A in the subsequent stage (step 4 in FIG. 5).
12, 414). Maximum volume from electronic volume 20 (attenuation 0d
The audio signals of L and R 2ch output in B) are switched SW _P
It is input to the electronic volume 40 via the
After the volume is adjusted to dB, the front and rear systems are separated, and the front side is adjusted to 0 dB and the rear side is adjusted to -20 dB.

Therefore, the power amplifier 50 has an attenuation of -18 dB on the front side.
Output to the Glyco 60A on the rear side with an attenuation of -38 dB.

The power amplifier 50 to which the H-level P-CON signal has been input is in the operating state, power amplification of the front audio signal is performed, and the front L side speaker FL and the front R side speaker are provided.
Drive FR.

On the other hand, the microcomputer 62A of the glyco 60A, which receives the H-level P-CON signal, supplies power to the respective parts in the set to activate them (steps 710 and 712 in FIG. 8). Then,
The rear side audio signals of the L and R 2 channels are adjusted to have a predetermined glyco characteristic by the glyco unit 64 and then output to the power amplifier 99 side.

The power amplifier 99 drives the rear L-side speaker RL and the rear R-side speaker RR by energizing the P-CON signal input from the player 30A via the glyco 60A to amplify the power of the rear-side audio signal.

The L and R 2ch signals output from the glyco section 64 are mixed by the mixing amplifier 68, and then separated into three bands of low band, middle band and high band by the BPFs 70 to 74. And each detector 76-80
DC detection is performed at and the signal level for each band is detected.

The detection signal from each detector 76-80 is A / D converter 82-86
It is output to the microcomputer 62A which is A / D converted by.

After the processing of step 712, the microcomputer 62A reads the data for each band from each of the A / D converters 82 to 86 and sets it as AD _{1 to} AD ₃ (step 714). Then, using the reference level data RD, the logarithm of AD ₁ / RD (which is an integer by rounding off, the same below) is obtained as LD _1, and the logarithm of AD ₂ / RD is obtained as LD ₂ .
The logarithm of AD ₃ / RD is calculated and set as LD ₃ (step 716).

Here, when the gain variable of ± 12 dB is made in the glyco section 64 of the glyco 60A, the attenuation of the audio signal input to the glyco section 64 at the electronic volume 40 is -20 dB (the attenuation at the electronic volume 20 is 0 dB), and spectrum analyzer indication shall be made at an appropriate level.

In reality, the electronic volume 40 varies from 0 dB to -90 dB, so if the attenuation becomes smaller than -20 dB, almost all display elements of the LCD displays 94 to 98 will be in the lighting state, or the reverse. In addition, if the attenuation is larger than −20 dB, LC
Almost all display elements of the D displays 94 to 98 may be turned off.

Therefore, in this embodiment, when the attenuation amount in the electronic volume control 40 is different from -20 dB, the display data is created after correcting LD _{1 to} LD ₃ to change the sensitivity of the spectrum analyzer display.

That is, the microcomputer 62A continues to step 716 corrected by adding an SD to each of the LD ₁ to Ld ₃ Request LD ₁ '~LD _3' (step
718). In this case, SD = 18, which increases the sensitivity.
Then, display data is created for each band from LD _{1 to} LD ₃ ′ and output to the corresponding LCD drivers 88 to 92 to perform spectrum analyzer display (step 720).

If the sensitivity is not changed, the signal level input to the graphic 60A is small, and many of the display elements of the LCD displays 94 to 98 are turned off, making it difficult to compare the band-by-band levels.

If there is no electronic volume on the output stage of the CD player,
A large audio signal is input to the Glyco 60A with 0 dB of attenuation. At this time, if the mode is switched to the normal mode, the microcomputer 60A subtracts 20 from LD ₁ to LD ₃ to perform sensitivity suppression correction, creates display data from the correction result, and LCD driver 88 to 9
It is designed to output to 2 (see steps 722 to 734).

After the process of step 720, the microcomputer 62A determines whether or not there is a control signal input including data related to the volume from the player 30A and whether or not the input of the P-CON signal is stopped (step of FIG. 9). (800, 802), if both are NO, the process returns to step 714 of FIG. 8 again to perform the spectrum analyzer display processing as described above.

Here, when the user turns on the volume up key of the operation unit 42 of the player 30A once to increase the volume, the microcomputer 34
Determines YES in step 600 of FIG. 7 and increases VD by 2 to -16 (step 608). Then volume code and V
A control signal composed of data DATA including D, clock CLK, and strobe STR is output to the electronic volume 40, and the attenuation amount of the volume electronic volume 40A is set to -16 dB (step 61
0).

As a result, the audio signal level output from the player 30A is increased by 2 dB on both the front and rear sides, and the speaker output is increased.

The control signal output from the microcomputer 34 is also input to the microcomputer 62A of the glyco 60A. The microcomputer 62A that has received the control signal determines YES in step 800 of FIG. 9, reads the data, and rewrites VD '(steps 804-80).
8). VD '=-16. Next, because it is rear mode −
Calculate (VD '+ RFD' + 20) and set it as SD (step 81
0, 812). SD = 16.

As a result, when the microcomputer 62A next performs the process of step 718 in FIG. 8, the LD _{1 to} LD ₃ are subjected to the sensitivity increase correction by 16 (dB).

The amount of attenuation of the audio signal input to the Glyco 60A is 2
Since it is reduced by dB, the increase in sensitivity is 2d
By reducing B, the spectrum analyzer display at the optimum level is secured.

Similarly, when the user turns on the volume up key of the player 30A eight times in succession, finally VD = 0, and the attenuation amount of the volume electronic volume 40A of the electronic volume 40 = 0 dB.
Becomes At this time, SD = in microcomputer 62A of Glyco 60A
The sensitivity correction for LD ₁ to LD ₃ in step 718 is 0 (dB).

The amount of attenuation of the audio signal input to the glico unit 60A is only -20 dB at the rear fader electronic volume 40C, and if the sensitivity correction is 0 (dB), the spectrum analyzer display is just at the optimum level.

After that, when the R side fader key of the player 30A is turned on once, the microcomputer 34 determines YES in step 606 of FIG. 7, F2 is incremented by 2 to -18, and since F is negative, FFD remains 0 and RFD only. -18 (steps 612 to 616).

Subsequently, a control signal including FFD is output to the electronic volume 40, and the attenuation amount of the front side fader electronic volume 40B is kept at 0 dB. Next, output the control signal including RFD to the electronic volume 40, and use the electronic volume for the rear fader.
The attenuation of 40C is set to -18dB (step 618).

As a result, the audio signal output to the rear side is increased by 2 dB.

The microcomputer 62A of the glyco 60A, which receives the control signal including the former FFD, reads the data (steps 800 and 804 in FIG. 9), but since the input FFD is the same as FFD ', FFD'
Is not rewritten (NO in steps 806 and 814).

When the control signal including the latter RFD is subsequently input, RFD ′ is different from RFD ′ and RFD ′ is rewritten with the RFD input this time (YES determination in steps 800, 804, 806, and 816, 818).

Then, since it is the rear mode, − (VD ′ + RFD ′ + 20) is calculated and set as SD (steps 810 and 812). SD = -2.

As a result, when the microcomputer 62A next performs the process of step 718 in FIG. 8, the sensitivity of LD _{1 to} LD ₃ is suppressed by 2 (dB).

The audio signal input to the Glyco 60A has an attenuation of −2
Since it is reduced by 2 dB from 0 dB, the suppression of the sensitivity is also increased by 2 dB, so that the spectrum analyzer display at the optimum level is secured.

Similarly, when the user turns on the R side fader key of the player 30A eight times in a row, finally FFD = 0, R
FD = -2, and the attenuation of the electronic volume 40B and 40C for the front and rear faders of the electronic volume 40 is 0-
2 dB (steps 606 and 612 to 618 in FIG. 7 are repeated). At this time, SD =-in the microcomputer 62A of the Glyco 60A
Will be 18.

When the R side fader key is turned on once, the player 30
Since the microcomputer 34 of A does +2 F after F = 0, FFD, RFD
Is set to 0, and the attenuation amounts of the front side and rear side fader electronic volumes 40B and 40C are both set to 0 dB (steps 606, 612, 614, 620 and 618 in FIG. 7).

At this time, SD = -20 in the microcomputer 62A, and step 718
The correction for LD ₁ to LD ₃ is −20 (dB).

The audio signal input to the glico unit 60A has 0 attenuation.
It is in dB, and if the correction is -20 (dB), the spectrum analyzer display will be the optimum level.

When the R side fader key is turned on once more, the microcomputer 34
Then sets FFD to -2 while keeping RFD at 0, and controls the electronic volume 40 based on these data (steps 606, 612, 614, 622, 618 in FIG. 7). The attenuation at the front fader electronic volume 40B is -2 dB. Attenuation at the rear fader electronic volume 40C is 0
It is left in dB.

Therefore, the speaker output on the front side becomes slightly smaller,
The speaker output on the rear side does not change.

The microcomputer 62A of the Glyco 60A inputs a control signal including FFD to rewrite FFD '(steps 800, 804, 8 in FIG. 9).
(06, 814, 820), SD is not changed because it is rear mode (steps 810, 812). When a control signal including RFD is subsequently input, SD is not changed because it is 0 dB, which is the same as RFD '(NO determination in step 816).

Similarly, when the R side fader key is turned on, only the front speaker output level is reduced, the rear speaker output level does not change, and SD remains at -20.

Attenuation of audio signal input to Glyco 60A is 0 dB
As it is, the spectrum display is performed at the optimum level by suppressing the sensitivity using SD.

Here, in order to listen to the CD instead of the tape, the player 30
When the CD is inserted in A, the microcomputer 34 detects the loading detection signal from the CD insertion detection unit 32 and the loading mechanism unit 36
Control to load the CD (step 40 in FIG. 5).
4, 416), CD when it is set in the CD playback / mechanical unit 38
It is determined that there is (step 402) and the flag C is set.

Then, when the user turns on the PLAY key, the CD playback / mechanical section
PLAY control is performed on 38 to start the reproduction of the CD (steps 406, 418, 420). Then, switch SW _P is switched to the A side, and the output to the subsequent stage of the P-CON signal continues,
Output the H-level RST signal to the deck 10A (step 42)
2, 424). Also, set flag P and drop Q (step
426).

In the deck 10A to which the RST signal is input, the microcomputer 14 determines YES in step 200 of FIG. 3, and the flag D is set. Therefore, the cassette playback / mechanical portion 18 is stopped and the tape running is stopped. The loading mechanism 16 is controlled to eject the cassette (steps 206 to 210).

At this time, the microcomputer 14 sets the P-CON signal to the L level to stop the output, clears the flags D and E, and sets F (steps 212 to 216).

The audio signal relating to the CD output from the CD reproducing / mechanical unit 38 is output to the power amplifier 50 and the glyco 60A via the switch SW _P and the electronic volume 40, and is acoustically reproduced by the front and rear speakers.

The audio signal related to the CD is also attenuated by VD + FFD on the front side and output to the power amplifier 50 on the electronic volume 40 according to the volume variable operation and the fader variable operation on the operation unit 42, and the rear side is attenuated by VD + RFD by the glyco 60A. Is output. However, as described above, V
Since the sensitivity is changed according to the size of D + RFD, the spectrum analyzer display is always displayed at the optimum level even if the volume change operation or the fader change operation is performed by the player 30A.

Note that the signal output from the front of the player 30A is the 60 G
In the case of a system configuration in which the input is input to, the mode selector switch 63 may be switched to the front mode, and SD is obtained based on VD and FFD input from the player 30A at this time (steps 700, 736 to 744 in FIG. 8, or Steps 810 and 822 in FIG. 9).

Also, when the electronic volume of the audio source device connected to the front stage of the glyco 60A can only change the volume, it is sufficient to switch the mode selection switch 63 to the volume mode, and SD is calculated based on the VD input from the front stage set ( Steps 700, 746 to 750 in FIG. 8 or steps 810, 824 in FIG. 9).

According to this embodiment, in the system in which the player 30A with an electronic volume is connected in front of the glyco 60A,
The control signal for the electronic volume 40 in the player 30A is also output to the subsequent glyco 60A, and is related to the volume data VD, rear side fader data RFD, or front side fader data FFD included in the control signal 62A of the microcomputer 60A. The correction data SD is calculated by knowing the amount of attenuation of the audio signal input to the glyco 60A at the electronic volume 40, and the data input from the A / D converters 82 to 86 for each band and the predetermined reference level data. SD was added to the logarithm of the ratio to RD to change the sensitivity, and then display data was created and output to the corresponding LCD drivers 88-92 for the display of the spectrum analyzer. And variable operation (volume variable operation and fader variable operation)
Regardless of this, the spectrum analyzer is displayed as if the attenuation amount in the electronic volume 40 of the audio signal input to the glyco 60A is constant at -20 dB, so the spectrum analyzer can always be displayed at the optimum level.

Note that the audio source device connected to the preceding stage of the glyco is not limited to the CD player, and may be another device such as a deck or a tuner.

The fixed values 20 and -20 in steps 744, 709, 722 of FIG. 8 and steps 812, 822, 824 of FIG. 9 are not limited to these values, and other fixed values may be used as long as they are suitable for the system configuration. It may be a value.

[Effect of device]

According to the in-vehicle audio system according to the present invention, the control means of the audio source device outputs the data related to the volume to the graphic equalizer device in the subsequent stage, and the spectrum canceler means of the graphic equalizer device outputs the data related to the volume. Equipped with sensitivity changing means for changing the sensitivity of the spectrum analyzer display, it is possible to always display the spectrum analyzer at the optimum level regardless of the volume-related variable operation in the audio source device in the preceding stage of the graphic equalizer device. It is easy to compare the signal levels for each band, and the setting operation to a desired graphic characteristic becomes easy.

[Brief description of drawings]

FIG. 1 is a block diagram showing the construction of an in-vehicle audio system according to one embodiment of the present invention, FIGS. 2 to 4 are flow charts showing the operation of the microcomputer of the cassette deck in FIG. 1, and FIG. 7 to 7 are shown in FIG.
A flowchart showing the operation of the microcomputer of the CD player, and FIGS. 8 and 9 are flowcharts explaining the operation of the microcomputer of the graphic equalizer. FIG. 10 is a block diagram showing a conventional vehicle-mounted audio system, and FIG. 11 is a block diagram showing an internal configuration of the electronic volume shown in FIG. Explanation of main symbols 30A: CD player, 34: Microcomputer, 40: Electronic volume, 60A: Graphic equalizer, 62A: Microcomputer, 66A: Spectrumr section.

Claims (1)

[Scope of utility model registration request] 1. An audio source device and a graphic equalizer device are connected in tandem in a front and rear direction, and the audio source device is provided with an electronic volume provided in an output stage, an operating means for performing a variable operation related to a sound volume, and an operating means. In accordance with the control means for outputting the data related to the volume to the electronic volume to perform the variable control related to the volume, the graphic equalizer device is equipped with the spectrum analyzer means for displaying the level of each band of the audio signal by the spectrum analyzer. In the audio equipment, the control means of the audio source equipment outputs the data related to the volume to the graphic equalizer equipment in the latter stage, and the spectrum analyzer means of the graphic equalizer equipment changes the sensitivity of the spectrum analyzer display based on the data related to the volume. Equipped with sensitivity changing means Vehicle audio system comprising the fact, the.