JPH0221817Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an antenna device for a radio receiver using a head-on cord as a receiving antenna.

Structure of the conventional example and its problems FIGS. 1 and 2 show the conventional example. FIG. 1 shows a radio receiver using a headphone cord as an antenna. 1 is the FM antenna terminal, 2 is the capacitor, 3 is the AM/FM tuner section, 4 is the volume adjuster,
5 is a volume amplifier, 6 is a chain coil inserted in series with the output line of the volume amplifier 5, 7 is a chain coil inserted in series between the ground terminal of the headphone jack 9 and the ground, 8 is a headphone, and 18 is a
This is a bar antenna for AM reception. Furthermore, AM・
The FM selector switch is omitted. Further, it is assumed that the above-mentioned chiyoke coils 6 and 7 have relatively large impedance in the FM reception band.

In this configuration, when the headphone 8 is inserted into the headphone jack 9, the cord of the headphone 8 becomes an FM antenna, and the received signal is transmitted from the ground terminal of the headphone jack 9 via the capacitor 2 to the AM/FM tuner unit 3. is guided to FM antenna terminal 1. Therefore, it was possible to eliminate the FM rod antenna, and this configuration was particularly effective for small radio receivers.

Figure 2 shows a tape recorder with a radio;
This is a direct application of the configuration shown in the figure. 1st
Components with the same numbers as those in the drawings are the same, so their explanations will be omitted. 10 is a playback head, 11 is a playback preamplifier, 12 is a radio tape selection switch, 1
3 is a power supply. 14 is tuner block,
It includes an AM/FM tuner 3, a changeover switch 12, and a capacitor 2. 15 is a tape recorder block which includes the above-mentioned playback head 10, playback preamplifier 11, volume adjuster 5, choke coil 6,
7, including a headphone jack 9. 16 is a connecting line. In this structure, a tuner block 14 and a tape recorder block 15 are connected to each other by a connecting wire 16 having a plurality of core wires. 16A is a power line, 16B and 16C are signal lines, 16D is a ground line, and 16E is an antenna signal supply line.

In this tape recorder with radio, when the radio/tape selector switch 12 is on the tape side T,
The signal from the reproduction head 10 is transmitted to the reproduction preamplifier 11.
The signal is amplified through the signal line 16B, the radio/tape selector switch 12, and the signal line 16C to the volume controller 4, passes through the volume amplifier 5, and drives the headphone 8 connected to the headphone jack 9. When the radio tape selector switch 12 is on the radio side R, the signal from the AM/FM tuner section 3 is guided to the volume adjuster 4 and volume amplifier 5 via the signal line 16C, and is connected to the headphone jack 9. It is configured to drive the headphone 8. During this radio reception, the cord of the headphone 8 serves as an FM antenna, similar to the radio receiver shown in FIG. The signal is input to the FM tuner section 3.

However, in the conventional tape recorder with radio, when the tuner block 14 and the tape recorder block 15 are coupled by the coupling line 16, the capacitance between each line in the coupling line 16 is several tens of pF, so that the antenna signal is not transmitted through the antenna signal supply line 16E. A drawback is that most signal components are attenuated by the line capacitance. Furthermore, when the high-frequency characteristics of the volume amplifier 5 are extended during AM reception, the chiyoke coils 6 and 7 are electromagnetically coupled to each other, resulting in an increase in noise.

Purpose of the invention The present invention solves the above-mentioned conventional drawbacks.
It is an object of the present invention to provide an antenna device that can provide an antenna with extremely low attenuation when receiving FM, and on the other hand, can perform good reception without generating induced noise when receiving AM.

Structure of the invention The present invention separates a tuner part and a power amplifier part, connects them with a connecting wire having a large number of core wires, and connects the power amplifier's output line and output ground line among the core wires of the connecting wire in the tuner part. One end of the first and second choke coils is connected in series to each of the above, a headphone cord is connected to the other end of the first and second choke coils, and a second cord is connected to the output ground line. The connection point between the York coil and the headphone cord is connected to the antenna input terminal of the tuner section via a capacitor, and the headphone cord is used as an antenna wire.

DESCRIPTION OF EMBODIMENTS FIG. 3 shows a circuit diagram of a tape recorder with a radio to which an embodiment of the present invention is applied. Here, the same members as in FIG. 2 are given the same numbers and detailed explanations will be omitted. A tape recorder block 19 includes a playback head 10, a playback preamplifier 11, a volume adjuster 4, a volume amplifier 5, a headphone jack 9, and a power supply 13. 20 is AM/FM tuner section 3,
This tuner block has a radio/tape selector switch 12 and a bar antenna 18 for AM reception. 16 is a connection line, 16A is a power line, 16B,
16C is a signal line, 16D is a ground line, 16F is an output line, and 16G is an output ground line.

One ends of the output line 16F and output ground line 16G are connected to the signal side terminal and ground terminal of the headphone jack 9 of the tape recorder block 19, respectively. Also output line 16F, output ground line 1
The other end of 6G is connected to one end of chain coils 21 and 22 installed in tuner block 20. Furthermore, a cord 17a of another headphone 17 is connected to the other ends of the chain coils 21 and 22. The connection point between the chiyoke coil 22 and the headphone cord 17a and the AM/FM tuner section 3
A capacitor 2 is connected between the FM antenna terminal 1 and the FM antenna terminal 1.

According to the configuration of this embodiment, the output of the volume amplifier 5 can drive the headphone 17 via the output line 16F, the output ground line 16G, the choke coils 21 and 22, and the cord 17a. on the other hand,
By setting the values of the choke coils 21 and 22 to values having large impedance in the AM reception band, FM radio waves are inputted from the cord 17a of the headphone 17 via the capacitor 2 to the FM antenna terminal 1. That is, headphone 17
It is possible to use the cord 17a as an antenna wire, and since the received signal does not pass through the connection line 16, it is possible to prevent the received signal from decreasing.

Furthermore, if the headphone 8 is attached to the headphone jack 9 of the tape recorder block 19 while the tape recorder block 19 and tuner block 20 are connected by the connecting wire 16, the output of the volume amplifier can be listened to using the headphone 7. Can be done. At this time, the FM antenna terminal 1 of the FM/AM tuner section 3 is connected to the capacitor 2.
It is connected to the ground terminal of the headphone jack 9 through a series circuit of the yoke coil 22 and
The cord of the headphone 8 does not function as an FM antenna line due to the configuration of the series circuit of the choke coil 22 and the capacitor 2, and no operational problems occur.

Further, it is desirable that the polarities of the side of the chain coils 21 and 22 connected to the cord 17a of the headphone 17 be the same. With this configuration, the chiyoke coils 21 and 22 do not cause electromagnetic inductive coupling with each other, and an increase in noise during AM reception can be prevented.

Effects of the invention The present invention separates the tuner section and the power amplifier section and connects them with a connecting wire having a plurality of core wires.
Connect the power amplifier's output line and the output ground line of the connecting wires to one end of each of the two check coils attached to the tuner section, connect the headphone cord to the other end of each of these two check coils, and connect the headphone cord to the other end of the two check coils. Since the configuration is such that a capacitor is connected between the connection point between the grounding coil and the head-on cord and the antenna input terminal of the tuner section, the head-on can be connected from the power amplifier section through the output line and output ground wire in the connection line. At the same time, the cord of the headphone can function as an antenna line, and the received signal can be input to the antenna input terminal through a capacitor.Since the received signal does not pass through the connection line, there is little attenuation of the received signal. It has the following effects.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams of a radio receiver and a tape recorder with a radio, respectively, each equipped with a conventional antenna device, and FIG. 3 is a circuit diagram of a tape recorder with a radio equipped with an antenna device according to an embodiment of the present invention. It is a diagram. 1...FM antenna terminal, 2...capacitor,
3...AM/FM tuner section, 16...Connection line,
16F...Output line, 16G...Output ground line, 17
... Headphone, 17a... Code, 19...
Tape recorder block, 20... tuner block, 21, 22... chiyoke coil.

Claims (1)

[Claims for Utility Model Registration] (1) The tuner section and the power amplifier section are separated, and they are connected to each other by a connecting wire having a plurality of core wires including power supply lines and signal lines, and the above power amplifier section is connected in the tuner section. One end of each of the first and second check coils is connected to the output line and output ground line of the connection line connected to the output side of the amplifier section, and a headphone is connected to the other ends of the first and second check coils. In addition to connecting the cord, the connection point between the second choke coil connected to the output grounding wire and the headphone cord and the antenna input terminal of the tuner section are connected via a capacitor, and the headphone cord is used as an antenna wire. An antenna device configured for use. (2) The antenna device according to claim 1, characterized in that the first and second choke coils are connected to the headphone in a direction in which their polarities match.