JPH073443Y2 - 2 channel tape playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a two-channel tape reproducing apparatus, and in particular, an audio signal is recorded in one channel and a data signal, for example, MFM modulated, is recorded in the other channel. Also, it relates to a device for reproducing such a two-channel tape.

(Prior Art) Conventionally, as a device for reproducing a two-channel tape in which an audio signal and a data signal are recorded, Japanese Patent Laid-Open No. 56-13378
No. 2 or Japanese Patent Publication No. 56-14986 is known. However,
In these two-channel tape reproducing devices, when reproducing a two-channel tape, if there is no audio signal and there is only a data signal, crosstalk causes
The data signal is output as noise to the audio signal path.

In order to prevent such audible noise, conventionally, a method of recording a data signal smaller than an audio signal by providing a level difference between the audio signal and the data signal, and an erase part between two channels are used. The method of forming is known.

(Problems to be solved by the invention) However, in the former method, since the level of the data signal is small, not only the audio signal affects the data signal but also the speed (Baud rate) of the data signal is limited. . In the latter method, when dubbing such a tape, a step of forming a gap corresponding to the erased portion is required after recording once, and therefore, there is a problem that the dubbing cost increases. .

Therefore, the main object of this invention is to provide a reproducing apparatus for a two-channel tape in which a data signal does not occur as audible noise.

(Means for Solving the Problems) Briefly stated, the present invention is a two-channel tape reproducing apparatus in which an audio signal is recorded in a first channel and a modulated data signal is recorded in a second channel. And a first signal path for the audio signal read from the first channel, a second signal path for the data signal read from the second channel, a first signal path A two-channel tape reproducing apparatus comprising a muting circuit which is provided to mute the signal of the first signal path, and a control means which activates the muting circuit when the audio signal of the first channel becomes silent. is there.

(Operation) When the audio signal of the first channel becomes silent,
The muting circuit is activated by the control means.
Therefore, (the signal of) the first signal path is muted. Therefore, at that time, nothing is produced as the audio output from the speaker.

(Effect of the Invention) According to the present invention, since the first signal path (the signal) is muted when the audio signal is in a silent state, even if the data signal is being reproduced at that time, audible noise caused by the data signal is generated. Does not occur. Therefore, it is not necessary to form a level difference between two signals or to form a band gap as in the conventional case. Therefore, according to this invention, all the above-mentioned problems can be solved.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments below with reference to the drawings.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention.
The tape 10 comprises two channels 10a and 10b, one channel 10a recording an analog audio signal or audio signal and the other channel 10b recording a digital signal, for example an MFM modulated data signal. There is. An audio head 12 is provided in association with one channel 10a of this tape 10 and the other channel
A data head 14 is provided in association with 10b.

The signals reproduced by the heads 12 and 14 are amplified by the reproduction amplifier 16 and the data amplifier 18, respectively, and then supplied to the equalizer 20 and the waveform shaping circuit 22, respectively.

The audio signal that has passed through the equalizer 20 is amplified by the low frequency amplifier 24, and is supplied to the output amplifier 28 through the muting circuit 26. On the other hand, the data signal reproduced as a digital signal by the waveform shaping circuit 22 is demodulated by the MFM demodulation circuit 30, and as predetermined bit data,
Given to the microcomputer 32. The output based on the processing result of the microcomputer 32 is, for example, in synchronization with the sound based on the audio signal to move the movable part (not shown) of the doll, or the image processing device or the TV game machine connected to the TV receiver. It is used as a control signal for changing the display state of.

For example, a speaker (not shown) is connected to the output amplifier 28, so that the audio signal reproduced from the audio head 12 is output as voice. The data signal provided to the microcomputer 32 is processed by the microcomputer 32 as needed.

The output of the regenerative amplifier 16 included in the first signal path is provided to the retriggerable monostable multivibrator 34. The output duration of the monostable multivibrator 34 is set to, for example, 0.2 seconds. The retriggerable monostable multivibrator 34 is triggered at every rising edge (edge with positive derivative) or falling edge (edge with negative derivative) of the audio signal from the playback amplifier 34, and 0.2 times after being triggered. It is such a monostable multivibrator whose output goes low after seconds.

In operation, the two channels 10a and 10b of the tape 10
If an audio signal and a data signal are recorded respectively on the first signal path (the audio signal path including 12, 16, 24 and 28) and the second signal path (14, 1).
Data signal paths including 8, 22, 30, and 32) are both enabled to reproduce the required audio and data signals, respectively.

When no audio signal is recorded on one channel 10a, i.e. when the audio signal on channel 10a is silent, there is no signal from the regenerative amplifier 16 and therefore the retriggerable monostable multivibrator 34 is no longer triggered. After 0.2 seconds, the output becomes low level. This low level output is provided to the muting circuit 26, and thus the muting circuit 26 invalidates this first signal path. That is, in response to the low level signal from the retriggerable monostable multivibrator 34, the muting circuit 26 shuts off the path between the low frequency amplifier 24 and the output amplifier 28 or forces it to ground. Therefore, no signal is given to the output amplifier 28, and no audible noise due to the data signal is output from the speaker (not shown) connected thereto.

FIG. 2 is a block diagram showing another embodiment of the present invention. In this embodiment, the output of output amplifier 28 is RF modulator 36.
And the data processed by the microcomputer 32 are also supplied to the RF modulator 36.
The RF modulator 36 mixes an input audio signal and a data signal (which becomes an image signal) to generate, for example, an NTSC color composite signal for a TV receiver. Therefore, the RF modulator 36 is connected to the TV receiver 38, and in the TV receiver 38, the audio signal reproduced from one channel 10a of the tape 10 and the image based on the data signal output from the other channel 10b are imaged. Will be output or displayed respectively.

In this embodiment, the retriggerable monostable multivibrator 40 is also provided in the data signal path, i.e. the second signal path. That is, the output of the regenerative amplifier 18 is provided as the trigger input of the retriggerable monostable multivibrator 40. Each time this data signal rises or falls, this retriggerable monostable multivibrator 40
Is triggered.

Two retriggerable monostable multivibrators 34 and
Both outputs of 40 are given to predetermined input terminals of the microcomputer 32. A control signal for controlling the muting circuit 26 is output from the output terminal of the microcomputer 32.

In operation, when an audio signal and a data signal are recorded in the two channels 10a and 10b, respectively, as described above, the TV receiver 38 displays and reproduces an image corresponding to the reproduced data signal. Audio signal is being output.

The microcomputer 32, based on the respective outputs of the retriggerable monostable multivibrators 34 and 40,
Determine if an audio signal is present and also at the same time a data signal is present. If the data signal is present and the audio signal is not present, the microcomputer 32 outputs the control signal from the output terminal. In response, the muting circuit 26 operates,
The first signal path is disabled as in the previous embodiment.

In this embodiment, the microcomputer 32 outputs the control signal to operate the muting circuit 26. However, even if a gate circuit is used, which receives the outputs of the two retriggerable monostable multivibrators 34 and 40 and outputs some signal when the signal from the former is at the low level and the signal from the latter is at the high level, Good.

Further, in the embodiment shown in FIG.
If it is not necessary to output an audio signal, regardless of the presence or absence of an audio signal or a data signal, that is,
Regardless of the output of the retriggerable monostable multivibrators 34 and 40, a control signal for the muting circuit 26 can be output to disable the audio signal path.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing another embodiment of the present invention. In the figure, 10 is a two-channel tape, 26 is a muting circuit, 32 is a microcomputer, and 34 and 40 are retriggerable monostable multivibrators.

Claims (3)

[Scope of utility model registration request] 1. An audio signal on a first channel, a second audio signal on a second channel.
A two-channel tape reproducing apparatus in which a modulated data signal is recorded in each channel, a first signal path for an audio signal read from the first channel, the second channel A second signal path for a data signal read from the muting circuit, a muting circuit provided in the first signal path for muting a signal of the first signal path, and an audio signal of the first channel A two-channel tape reproducing apparatus comprising control means for activating the muting circuit when the audio signal becomes silent. 2. The two-channel tape according to claim 1, wherein the control means activates the muting circuit after a certain period of time from when the audio signal of the first channel becomes silent. Playback device. 3. The two-channel tape according to claim 1 or 2, wherein the control means activates the muting circuit when the data signal is recorded in the second channel. Playback device.