JPS6213209Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a magnetic recording/playback device capable of recording and reproducing audio multiplexed television signals.

In order to record and play back audio multiplexed television signals with a magnetic recording/playback device, a tuner and a modulator for audio multiplexing are provided, and during recording, the tuner outputs the main audio signal in the case of different types of (duplex) audio. In the case of stereo, the left side signal and the right side signal are taken out and recorded on tape, and this is supplied to a modulator to be converted into a VHF signal and supplied to a monitor receiver, and during playback, it is played back from the tape. Similarly, the main audio signal and sub audio signal or the left signal and right signal are supplied to the modulator.
It is sufficient to convert it into a VHF signal and supply it to the receiver, but in this case, both during recording and playback,
It is necessary to switch the modulator between different types of audio and stereo.

However, manually performing this switching by the user is not only troublesome but also prone to errors.

By the way, audio multiplexed television signals include
Control signals with different frequencies are inserted for different types of audio and for stereo.

This invention focuses on this point and uses this control signal to automatically switch the modulator.

That is, in this invention, during recording, the modulator is switched according to the pilot signal detected by the tuner, and this pilot signal is recorded on the tape, and during playback, the modulator is switched according to the pilot signal reproduced from the tape. Switch.

FIG. 1 shows the recording system in which an audio multiplexed television signal received by an antenna 10 is supplied to an audio multiplexing tuner 20, and when the audio is of a different type, a main audio signal M is sent to its two output terminals. When the sub audio signal S is stereo, a left signal L and a right signal R are separately taken out, and are sent to the recording amplifier 3 through the audio circuits 31 and 41.
2 and 42 to heads 33 and 43, and are recorded on separate audio tracks along the length of magnetic tape 50.

At the same time, the two signals passing through the audio circuits 31 and 41 are supplied to a VHF modulator 60 for audio multiplexing, and are also sent to another output terminal of the tuner 20 depending on the frequency difference of the control signals, for example, for different types of audio. A pilot signal S _P is obtained which is at high level at times and at low level at stereo.
This signal is supplied to the modulator 60, which is switched according to the pilot signal S _P to obtain a VHF signal of an open channel, which is used in a television receiver for audio multiplexing. 100 or an audio multiplex adapter with a tuner.

The VHF modulator 60 is configured, for example, as shown in FIG.
The signal through the audio circuit 41 is supplied from the terminal 61 to one input terminal A of the switch circuit 63, the signal through the audio circuit 41 is supplied from the terminal 62 to one input terminal A of the switch circuit 64, and the signal from the terminals 61 and 62 are supplied to the adder 65 and added, the added signal is supplied to the other input terminal B of the switch circuit 63, and the signals from the terminals 61 and 62 are supplied to the subtracter 66.
The latter is subtracted from the former, the subtracted signal is supplied to the other input terminal B of the switch circuit 64, and the pilot signal S _P is supplied as a switch signal to the switch circuits 63 and 64, so that the pilot signal _SP When is at a high level, that is, when it is a different type of audio, the switch circuits 63 and 64 are respectively switched to the input terminal A side, and the main audio signal M is obtained from the circuit 63, and the sub audio signal S is obtained from the circuit 64. When the pilot signal S _P is at a low level, that is, when it is stereo, the switch circuits 63 and 64 are respectively switched to the input end B side, and the sum signal L+R of the left signal L and the right signal R is output from the circuit 64. Difference signals L−R are obtained, and the main audio signal M or sum signal L+R from the circuit 63 is supplied as is to the synthesizer 67, and the sub audio signal S or the difference signal L from the circuit 64 is
-R is supplied to the FM modulation circuit 68 and 31.5kHz
The audio subcarrier is FM modulated, the modulated signal is supplied to a synthesizer 67, the output signal of the synthesizer 67 is supplied to an FM modulation circuit 69, and the audio carrier is FM modulated.

Further, the pilot signal S _P described above is supplied to the control signal duty variable circuit 70, and when the pilot signal S _P is at a high level, that is, when it is a different type of sound, the control signal S _CR is output as shown in FIG. 6C, for example. When the duty of the control signal S is set to 60 and the pilot signal S _P is at the low level, that is, when it is stereo, the duty of the control signal S _CR is, for example, as shown in C' in the same figure.
50, and the control signal _SCR whose duty changes depending on whether it is a different type of audio or stereo is supplied to the control head 80 and recorded on a control track along the longitudinal direction of the magnetic tape 50. .

The variable duty circuit 70 is composed of a flip-flop circuit 71 and a monostable _{multivibrator} 72, as shown in FIG. 4, for example.
is supplied to the flip-flop circuit 71 to obtain a signal SF (B in the same figure) which is inverted every vertical period, and this is supplied to the monostable multivibrator 72, and for example, the monostable multivibrator 72 is triggered at the rising edge of the signal SF. For example, the time constant of the monostable multivibrator 72 is switched by the pilot signal _SP , and the duty of the control signal S _CR obtained from the monostable multivibrator 72 is changed as described above.

Figure 2 shows the reproduction system with heads 33 and 43.
The main audio signal M and the sub audio signal S or the left side signal L and the right side signal R, which are reproduced from separate audio tracks of the tape 50 at A control signal reproduced from the control track of the tape 50 is supplied to the duty detection circuit 90, and a pilot signal S _P is obtained, which is high level when the sound is of a different type and low level when the sound is stereo. As supplied and recorded,
The modulator 60 is switched in response to the pilot signal S _P to obtain a VHF signal with an open channel, which is then supplied to the audio multiplexing receiver 100 or the audio multiplexing adapter with a tuner. Ru.

The duty detection circuit 90 is configured, for _example , as shown in _FIG . The control signal S _CP is taken out through the reproduction amplifier 91, and the positive pulse _P E) is taken out, which triggers the monostable multivibrator 93, which rises with a pulse _P
A signal S _M (FIG. F) between
A signal S _G (G in the same figure) which rises at the fall of the signal S _M is obtained and is supplied as a gate signal to the gate circuit 95. On the other hand, the control signal S _CP passed through the regenerative amplifier 91 is inverted by the inverter 96 and connected to the diode. 97 extracts the positive pulse of the inverted signal, that is, the inverted negative pulse of the original control signal _SCP , and supplies this to the gate circuit 95 to make the gate signal S _G high. The pulse P _YG from the gate circuit 95 is gated during the period of the level, and the pulse P
8 and held. When the voice is of a different type, the pulse P _Y supplied to the gate circuit 95 comes within the high level period of the gate signal S _G (H in the figure), and the pulse P _Y is supplied from the gate circuit 95.
_G is obtained (I in the same figure), the pilot signal S _P from the hold circuit 98 becomes high level (J in the same figure), and in the case of stereo, the pulse P _Y supplied to the gate circuit 95 becomes the gate signal S _G deviates from the high level period (H' in the figure), pulse P _YG is not obtained from the gate circuit 95 (I' in the figure), and the pilot signal S _P from the hold circuit 98 becomes low level (J in the figure). ').

In addition, the control signal S is applied to the servo during playback.
The positive pulses of _CP (FIG. 6D, D') are used.

As mentioned above, according to this invention, the modulator for audio multiplexing is automatically switched between different types of audio and stereo, both during recording and playback, so the user does not have to worry about any trouble. There are no errors at all.

[Brief explanation of the drawing]

Figure 1 is a system diagram of the recording system of the magnetic recorder/player of this invention, Figure 2 is a system diagram of the playback system, Figure 3 is a connection diagram of the VHF modulator for audio multiplexing, and Figure 4 is a diagram of the control signal. FIG. 5 is a system diagram of an example of a duty variable circuit, FIG. 5 is a system diagram of an example of a control signal duty detection circuit, and FIG. 6 is a waveform diagram for explaining the operation of the circuits shown in FIGS. 4 and 5. 20 is a tuner for audio multiplexing, 60 is a VHF modulator for audio multiplexing, 70 is a control signal duty variable circuit, and 90 is a control signal duty detection circuit.

Claims (1)

[Scope of utility model registration request] a tuner for audio multiplexing, a modulator for converting the audio signal output of the tuner into a television signal of a predetermined channel, a television receiver connected to the modulator, and a tuner for recording and reproducing the output of the tuner. and a recording and reproducing means, which switches the internal connection of the modulator in response to a pilot signal corresponding to the type of audio signal detected by the tuner during recording by the recording and reproducing means to correspond to the type of audio signal. means for supplying the television signal of the predetermined channel to the television receiver and recording the control signal by changing the duty ratio of the control signal of the recording and reproducing means according to the pilot signal; means for detecting the duty ratio of the control signal, switching the internal connection of the modulator according to the detection output, and supplying the television signal of a predetermined channel corresponding to the type of the audio signal to the television receiver; A magnetic recording/playback device characterized by: