JPS6225000Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an audio device equipped with a switch that is used both for operating a radio section that performs automatic channel selection and for operating a tape recorder section.

Conventionally, car stereos, which are audio equipment, are so-called multi-functional car stereos, which are equipped with a radio section and a tape recorder section that automatically select stations, and an amplification section that amplifies the audio signals from the radio section and tape recorder section. was devised, and a conventional multifunctional car stereo is constructed as shown in FIG. In the figure, A is a radio section that performs automatic tuning, and a stereo reception signal from an antenna 1 is input to a mixing circuit 3 via a high frequency amplification circuit 2. The stereo reception signal is mixed with the oscillation signal of the local oscillation circuit 4, and the stereo reception signal is converted to an intermediate frequency signal.The converted stereo reception signal is input to the intermediate amplification/detection circuit 5, which converts the stereo reception signal into a stereo signal. The received signal is demodulated, and the demodulated stereo received signal is separated into left and right audio signals by a multiplex circuit 6. Further, when performing automatic tuning, a frequency control signal from the control circuit 7 is input to the high frequency amplifier circuit 2 and the local oscillation circuit 4, and the control circuit 7 inputs the frequency control signal to the first resistor R1.
the first transistor for mutating Q1 through
A high-level channel selection muting signal is output to the base of the channel selection muting signal, the first transistor Q1 is turned on, and the multiplex circuit 6 is turned on.
The stereo reception signal is cut off.

B is the tape recorder section, and the left channel head Hl is the left channel equalizer circuit 8L.
is connected to the head for the right channel.
Hr is connected to the right channel equalizer circuit 8r. When selecting a song, the left and right audio signals from both equalizer circuits 8l and 8r are input to the automatic tuning circuit 9, so-called song interval detection is performed, and a drive command signal is sent from the automatic music selection circuit 9 to the plunger 10. output, plunger 10
By this operation, the tape recorder section B is switched from the song selection mode to the playback mode.

C is an amplifier section that amplifies the left and right audio signals from the radio section A and the tape recorder section B, and the left and right audio signals from the multiplex circuit 6 of the radio section A and both equalizer circuits 8l of the tape recorder section B. , 8r are input to the left channel amplifier circuit 11l and the right channel amplifier circuit 11r through the left and right volume adjustment volumes VRl and VRr, respectively, and both amplifier circuits 1
The outputs of 1l and 11r drive the left channel speaker SPl and the right channel speaker SPr, respectively. Q2 and Q3 are the second and third NPN type transistors that constitute the muting circuit 12.
transistor, both transistors Q2 and Q3
When turned on, the left and right audio signals to both volumes VRl and VRr are interrupted.

Sa is a first switch, that is, a radio/tape changeover switch, which is switched between when the radio section A is used and when the tape recorder section B is used. , ta respectively power terminal +B
A high level power signal is input from.
Sb and Sc are the automatic return type first and second channel selection switches, and the power signal from the radio section contact ra of the radio/tape selector switch Sa is input, and by operating both switches Sb and Sc, the radio section A It outputs an increase command signal and a decrease command signal of the selected frequency to the control circuit 7, respectively. Sd and Se are the second and third switches, that is, the fast forward switch and the rewind switch, which are operated respectively when the tape recorder section B is in the fast forward mode and rewind mode. One end is connected to the tape recorder contact ta of the radio/tape selector switch Sa, and the other ends of both switches Sd and Se are connected to the second and third transistors Q2 and Q3 via the second and third resistors R2 and R3, respectively. connected to the base. Sf is a music selection mute changeover switch that is switched when performing automatic music selection, and has an on contact on and an off contact off, and the high level music selection muting signal from the automatic music selection circuit 9 is passed through the on contact on to the second mute switch, Third resistor R2, R3
At the same time, the off contact OFF is grounded.

When using the radio section A, switch the radio/tape selector switch Sa to the radio section contact ra, and when performing automatic tuning, operate the first tuning switch Sb or the second tuning switch Sc. The control circuit 7 outputs an increase command signal or a decrease command signal for the tuning frequency, and outputs a frequency control signal from the control circuit 7 to the high frequency amplifier circuit 2 and the local oscillation circuit 4 to vary the tuning frequency and increase the frequency of the antenna. When the strength of the received signal from 1 exceeds a predetermined value, that is, when synchronization is achieved,
The output of the sensitivity meter terminal provided in the intermediate amplification/detection circuit 5 is input to the control circuit 7, which stops varying the tuning frequency, and the left and right audio signals from the tuned station are sent from the multiplex circuit 6 to the amplifier section C. is output. Note that while the tuning frequency is being varied, a tuning muting signal is output from the control circuit 7 to the first transistor Q1, and the left and right audio signals from the radio section A to the amplifier section C during the tuning frequency varying period are output. Both speakers SPl and SPr are muted.
This prevents unpleasant sounds from being output.

On the other hand, when using the tape recorder section B, the radio/tape selector switch Sa is switched to the tape recorder section contact ta, and when performing fast forwarding or rewinding, for example,
The fast forward switch Sd or the rewind switch Se is closed or locked, and the power signal via the radio/tape selector switch Sa is transferred to the fast forward switch.
It is input to the second and third resistors R2 and R3 of the muting circuit 12 via Sd or rewind switch Se, and the second and third transistors Q2 and Q3 are turned on to operate the muting circuit 12, allowing fast forwarding and rewinding. Amplifying section C for unpleasant audio signals generated during
input is prevented.

In addition, when performing automatic music selection, the music selection muting switch Sf is switched to the ON contact, and the music selection muting signal from the automatic music selection circuit 9 is transferred to the second and third resistors R2 and R3 of the muting circuit 12.
, and drives the muting circuit 12 to prevent unpleasant sounds from being output from both speakers SPl and SPr during the music selection period.

However, in the above case, six switches are required to use the radio section A and the tape recorder section B, which has the disadvantage that the operation space for each switch becomes large, which is a hindrance especially when trying to downsize the switch. However, the disadvantage is that the operation becomes complicated.

This invention was developed with the above points in mind, especially the first
The first and second channel selection switches Sb, Sc, fast forward switch Sd, and rewind switch Se in the figure are for radio section A.
This invention was devised by focusing on the fact that it is operated only when using either the tape recorder section B or the tape recorder section B. Next, this invention will be explained in detail with reference to FIG. 2 showing one embodiment of the invention.

In this figure, the same symbols as in FIG. 1 indicate the same things, and the differences from FIG. 1 are as follows.
In other words, fast forward switch Sd, rewind switch
Connect one end of Se to power terminal +B, and connect both switches.
First and second diodes D1 and D2 for backflow prevention are provided between the other ends of Sd and Se, and the first gate section 1
3 has two non-inverting input terminals, namely the first and second
input terminal and one inverting input terminal, i.e. the third
first and second AND gates G1, each having an input terminal;
In addition to providing G2, both AND gates G1 and G
Connect the first input terminal of 2 to the radio/tape selector switch.
The second input terminal of the first AND gate G1 and the third input terminal of the second AND gate G2 are connected to the other end of the fast forward switch Sd. Input terminal, 2nd
The second input terminal of AND gate G2 is connected to the other end of rewind switch Se, and both AND gates G1 and G
The output terminal of 2 is connected to the control circuit 7 of the radio section A, and the second gate section 14 is further provided with a 2-input third AND gate G3 and a 2-input OR gate G4, and one input of the third AND gate G3 is connected to the control circuit 7 of the radio section A. The terminal is connected to the connection point of the first and second diodes D1 and D2, and the other input terminal of the third AND gate G3 is connected to the tape recorder section contact ta of the radio/tape changeover switch Sa. The output terminal of G3 and the on contact of the music selection switch SF are on.
and connect it to one input terminal of OR gate G4,
The channel selection muting signal from the control circuit 7 is input to the other input terminal of the OR gate G4, and the output terminal of the OR gate G4 is connected to the second and third transistors Q2 and 3 through the second and third resistors R2 and R3, respectively. This is the point connected to the base of Q3.
In addition, the first and second channel selection switches Sb and Sc in Figure 1
And the first transistor Q1 is not provided.

When using the radio section A, the radio/tape selector switch Sa is switched to the radio section contact ra in the same way as described above, and when selecting a station, the fast forward switch Sd or the rewind switch Se is switched.
command to raise or lower the selected frequency. For example, when outputting a command signal to increase the tuning frequency to the control circuit 7, the fast forward switch Sd
from the first AND gate G1 to the control circuit 7.
When outputting a rising command signal to the control circuit 7 and, conversely, outputting a descending command signal of the selected frequency to the control circuit 7, operate the rewind switch Se and turn the second AND gate G.
2 outputs a descending command signal to the control circuit 7.

Then, based on the operation of the fast forward switch Sd or the rewind switch Se, the control circuit 7 operates, and the radio section A performs automatic tuning in the same manner as described above, and also receives a tuning mutating signal from the control section 7 during the automatic tuning period. is output, and the outputted channel selection muting signal is input to the muting circuit 12 via the Noah gate G4, and the second and third switches Q2 and Q3 of the muting circuit 12 are turned on to transmit the channel selection signal from the radio section A to the amplifier section C. The left and right audio signals are muted.

On the other hand, when using the tape recorder section B, the radio/tape selector switch Sa is switched to the tape recorder section contact ta, as described above, and when performing fast forward or rewind, the fast forward switch Sd or the rewind switch Se is locked. By locking both switches Sd and Se, the third AND gate G is output from both switches Sd and Se, respectively.
The power signal is input to the other input terminal of the third AND gate G3, and at this time, the power signal via the tape contact ta is input to one input terminal of the third AND gate G3. G
4 to the second and third mutating circuits 12 through
A muting signal is input to the resistors R2 and R3, and the muting circuit 12 operates to mute the left and right audio signals from the tape recorder section B to the amplifier section C during fast forwarding or rewinding.

Furthermore, when automatic music selection is performed when the tape recorder section B is used, a music selection muting signal is output from the automatic music selection circuit 9 to the Noah Gate G4 via the radio/tape changeover switch Sa,
A music selection mutating signal is inputted from No. 4 to the second and third resistors R2 and R3 of the muting circuit 12, and the second and third transistors Q2 and Q3 are turned on, so that the music selection signal is input from tape recorder section B to amplifier section C during automatic song selection. , the right audio signal is muted.

Therefore, according to the embodiment described above, the fast forward switch Sd and the rewind switch Se can be used in common as a tuning switch for instructing the control circuit 7 to raise and lower the tuning frequency, respectively, as shown in FIG. Compared to the previous case, two switches can be omitted, the operating space can be reduced, the size can be reduced, and the operability has been improved. This is an effective method for audio equipment where space is limited.

In the above embodiment, the receiving section is described as a radio section A, but it goes without saying that the receiving section may be for example for television reception.

As mentioned above, according to the audio equipment of this invention,
The second and third switches operated for fast forwarding and rewinding of the tape recorder section can also be used as a tuning switch for instructing the control circuit of the receiving section to raise or lower the tuning frequency. It is.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional audio device, and FIG. 2 is a block diagram of an embodiment of the audio device of this invention. A... Radio section, B... Tape recorder section, C
... Amplifying section, Sa ... Radio/tape selection switch, Sd ... Fast forward switch, Se ... Rewind switch, 7 ... Control circuit, 12 ... Muting circuit, 13 ... First gate section, 14 ... 2nd gate section.

Claims (1)

[Scope of utility model registration request] The receiving section includes a receiving section that performs automatic tuning, a tape recorder section, and an amplifying section for audio signals from the receiving section and the tape recorder section. In an audio device in which an amplifying section is provided with a muting circuit, a first switch is switched when each of the receiving section and the tape recorder section is used, and second and third switches are operated for fast forwarding and rewinding of the tape recorder section, respectively. switch, and a first gate section that outputs an increase command signal or a decrease command signal of the tuning frequency to the control circuit by switching to the receiving contact of the first switch and operating the second switch or third switch. and switching the first switch to the tape recorder contact, or switching the second switch or the third switch to the tape recorder contact point.
and a second gate section that outputs a muting command signal to the muting circuit by operating a switch.