JPH05128724A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain required information by storing the signal, which discriminates contents of an audio signal, in parts corresponding to the start and the end of a reproduced FM signal at the time of recording in the case that two rotating magnetic heads are alternately switched to record and reproduce the carrier wave modulated based on the signal in the audio signal band. CONSTITUTION:Reproduced FM signals taken out from two magnetic heads 5 and 6 are amplified by regenerative amplifiers 7 and 8 and are controlled by a reproducing head switching pulse to obtain two signals. A switch SW3 is provided for these two signals, and the circuit of a 1.3MHz BPF and a demodulating circuit 11 connected in series and the circuit of a 1-7MHz BPF 10 and a demodulating circuit 12 connected in series are provided in parallel with this switch SW3, and information required for demodulation from the reproduced FM signal to the audio signal is taken out from the switch SW3. A switch SW4 is provided in parallel with the switch SW3 and is provided with the circuit of a BPF 13 and a discriminating circuit 1 connected in series to discriminate between stereo sounds and dual sounds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for recording / reproducing by switching two rotating magnetic heads, and more particularly, to the contents of an audio signal recorded by the state of an FM signal used for recording / reproducing. The present invention relates to a magnetic recording / reproducing device for discriminating.

[0002]

2. Description of the Related Art Some magnetic recording / reproducing devices record and reproduce a carrier wave modulated based on an audio signal by alternately switching two magnetic heads. To record a stereo broadcast or a bilingual broadcast in this device, a carrier wave modulated according to an audio signal is recorded as it is. Further, at the time of reproduction, it is impossible for the apparatus itself to determine whether the content of the recorded signal is a stereo broadcast or a bilingual broadcast, and the output cannot be controlled at the final output stage.

[0003]

As described above, in the recording / reproducing of the conventional magnetic recording / reproducing apparatus, it is impossible to determine whether the recorded content of the audio signal is the stereo broadcast or the bilingual broadcast. There was a problem. Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a magnetic recording / reproducing apparatus capable of discriminating recorded contents without damaging a continuous reproduced FM signal. is there.

[0004]

In order to achieve the above object, in a magnetic recording / reproducing apparatus according to the present invention, two rotating magnetic heads are alternately switched and based on a signal in an audio signal band. A magnetic recording / reproducing apparatus for recording / reproducing a modulated carrier wave, wherein a discriminating signal for discriminating the content of an audio signal is recorded at portions corresponding to a start end and an end of a reproduced FM signal during recording.

[0005]

In the present invention having the above-mentioned structure, when recording, information such as stereo or dual voice is recorded at the portions corresponding to the start and end of the reproduced FM signal. Continuous reproduction F necessary to demodulate this to an audio signal when reproducing
The M signal can be retrieved without loss. At the same time, by separately extracting the start end and the end part, it is possible to discriminate between the stereo and the double voice.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a first embodiment of a magnetic recording / reproducing apparatus according to the present invention, and FIG. 1 is a block diagram of a recording system. As shown in the figure, the recording FM signal is supplied to the two magnetic heads 1 and 2 which rotate during recording through recording amplifiers 3 and 4, respectively. The supplied recording FM signal is shown in FIG.
The supply is continued without the need for switching by the HiFi-head switching pulse (H.SW.P) shown in (A). Here, the switches SW1 and SW2 connected to the subsequent stage of the recording amplifiers 3 and 4 are Hi shown in FIGS. 2 (B) and 2 (C).
It is controlled by the Fi recording control signal. That is, the switches SW1 and SW2 are in the open state when the signals shown in FIGS. 8B and 8C are "H", and the switches SW1 and SW2 are in the closed state when the signals are "L".

Switches SW1 and S1 controlled by a HiFi recording control signal shown in FIGS. 2B and 2C.
The recording FM signal supplied to the magnetic heads 1 and 2 through W2 has the waveforms shown in FIGS. Also, FIG.
Shows the state of the pattern in which the FM signals of FIGS. 2D and 2E are recorded on the tape. Thus, necessary information can be recorded by changing the signal pattern of the HiFi recording control signal shown in FIGS.

FIG. 4 is a block diagram for extracting the signal recorded in the state of FIGS. As shown in the figure, the reproduction FM signals extracted from the two rotating magnetic heads 5 and 6 are amplified by the reproduction amplifiers 7 and 8, and the signals shown in FIGS. 5B and 5C are output, respectively. It The signals (B) and (C) are controlled by the reproducing head switching pulse (H.SW.P) shown in FIG. Further, in FIG. 4, the switch SW3 has a band pass filter (B.3) of 1.3 MHz (hereinafter, this frequency is the carrier frequency of L of the audio FM signal according to the HiFi standard).
P. F) 9, a demodulation circuit 11 and a band pass filter (BPF) of 1.7 MHz (hereinafter, this frequency is the carrier frequency of R of the audio FM signal according to the HiFi standard).
10 and the demodulation circuit 12 are connected in parallel, and when the switch SW3 demodulates the continuous reproduction FM signal shown in FIG. 5D into an audio signal, necessary information can be taken out without loss.

Further, the signals shown in FIGS. 5B and 5C, which are the outputs of the regenerative amplifiers 7 and 8, are supplied to the switch SW4 connected in parallel with the switch SW3. This switch S
W4 is also the playback H.W. of FIG. SW. Although controlled by P, the magnetic heads respectively corresponding to the H section a and the L section b of this pulse are opposite to the switch SW3, and the discrimination FM signal shown in FIG. Can be taken out. A noise component is removed from this discrimination FM signal through a bandpass filter (BPF) 13 of an arbitrary frequency band, and the discrimination circuit 14 in the subsequent stage discriminates the presence or absence of the FM signal, and the discrimination signal of FIG. Take out. Therefore, it is possible to discriminate between stereo and dual voices based on this discrimination signal.

That is, in this embodiment, the recorded FM signal is muted for a short time during recording with respect to the portions corresponding to the start end and the end of the reproduced FM signal extracted during reproduction. Then, at the time of reproduction, the reproduction head switching pulse (H.S.P.) is taken out as a continuous reproduction FM signal, and the H.S.P. SW. Only the start and end portions before and after the switching with P are taken out, and the written stereo information or dual voice information is read and determined.

6 to 10 show a second embodiment of the magnetic recording / reproducing apparatus according to the present invention, and FIG. 6 is a block diagram of a recording system. As shown in the figure, the recording FM signal is continuously supplied to the two magnetic heads 21 and 22 which rotate during recording through the recording amplifiers 23 and 24, respectively. Here, the recording amplifier 2
1.3MHz trap 2 connected to the latter stage of 3, 24
5, 26 and 1.7 MHz traps 27, 28 are recorded in stereo or dual audio depending on the situation.
The head switching pulse (HS) shown in FIG.
W. The pulse signal of the trap control at the timing shown in FIG.
ON / OFF control of 30 is performed. Similarly, on / off control of the trap switches 31 and 32 is performed by the trap control pulse signal at the timing of FIG.

1.3 MHz trap switches 29, 3
If 1 corresponds to the time of stereo broadcast recording and 1.7 MHz trap switches 30 and 32 correspond to the time of dual audio broadcast recording, trap switch 29, 31 or trap switch 30 determines whether stereo broadcasting or dual audio broadcasting. ，
It suffices to control any one of 32, as shown in FIGS.
The control signal of the trap control shown in can be used for both. FIG. 8 is a trace pattern of the tape recorded according to these, and a signal in which the presence or absence of 1.3 MHz or 1.7 MHz is controlled is recorded in the mesh portion depending on the situation of stereo or dual voice.

FIG. 9 is a block diagram for extracting the recorded signal based on FIGS. 6 to 8. As shown in the figure, the signals taken out from the two rotating magnetic heads 33 and 34 are respectively amplified by the reproduction amplifiers 35 and 36, and the signals shown in FIGS. 10B and 10C are output as reproduction FM signals. To be done. The reproduced FM signals of (B) and (C) are shown in FIG.
The reproducing head switching pulse (HS) shown in FIG.
W. P), and these are switches SW5
To produce the continuous reproduced FM signal shown in FIG. 10 (D). This reproduced FM signal is 1.3 MH each
z, 1.7 MHz band pass filter (BPF)
It is output as a voice signal through 37, 39 and demodulation circuits 38, 40.

Furthermore, the outputs of the regenerative amplifiers 35 and 36 are the regenerative H.264 signals of FIG. SW. It is supplied to the switch SW6 controlled by P. Here, the relationship between the switch SW5 and the switch SW6 is opposite in phase, and the switch S5
In the case of W5, the reproduction H.264 of FIG. SW. When P is "H", the reproduced FM signal of FIG. 9C is taken out, and the switch SW6 takes out the reproduced FM signal of FIG. Then, the output of the switch SW6 becomes the discrimination FM signal shown in FIG. 8E, which corresponds to the mesh portion in FIG. This discrimination FM signal is 1.3 MH connected to the latter stage of the switch SW6.
z, 1.7 MHz band pass filter (BPF)
By passing through 41, 43 and discrimination circuits 42, 44,
Whether the signal controlled in the situation of stereo or dual voice at the time of recording is 1.3 MHz (assuming that it corresponds to stereo at the time of recording) or 1.7 MHz (assuming that it corresponds to dual sound at the time of recording). It is determined that the same figure (F), (G)
Can be taken out as the discrimination signal shown in. By using such a discrimination signal, when demodulating into an audio signal,
It is possible to discriminate between stereo and dual voice without damaging necessary information.

That is, in the present embodiment, the portions corresponding to the beginning and the end of the reproduced FM signal extracted at the time of reproduction are 1.3 MHz and 1.7 M at the time of recording stereo or dual voice.
One of two carrier waves of Hz is muted several times in a short time. Then, at the time of reproduction, while taking out as a continuous reproduction FM signal, only the start end and the end part before and after the switching by the reproduction head switching pulse (H.SW.P) are taken out, and by reading which one of the carrier waves is muted, The recorded contents can be discriminated.

[0016]

As described above, according to the magnetic recording / reproducing apparatus of the present invention, necessary information is lost when the reproduced FM signal extracted by the two rotating magnetic heads is demodulated into an audio signal. Without this, it is possible to record / reproduce information necessary for distinguishing between stereo and dual audio, for example.

[Brief description of drawings]

FIG. 1 is a block diagram of a recording system in a first embodiment of a magnetic recording / reproducing apparatus according to the present invention.

2A to 2E are waveform diagrams showing a control signal and an output signal controlled by the control signal in the embodiment of FIG.

3 is an explanatory diagram showing a state of a pattern in which an FM signal is recorded on a tape in the embodiment of FIG.

4 is a block diagram for retrieving the recorded signal in the embodiment of FIG.

5A to 5F are waveform diagrams showing the control signal in FIG. 4 and the output signal controlled by the control signal.

FIG. 6 is a block diagram of a recording system in a second embodiment of the magnetic recording / reproducing apparatus according to the present invention.

7A to 7C are waveform diagrams showing a control signal and an output signal controlled by the control signal in the embodiment of FIG.

FIG. 8 is an explanatory diagram showing a state of a pattern in which an FM signal is recorded on a tape in the embodiment of FIG.

9 is a block diagram for retrieving the recorded signal in the embodiment of FIG.

10A to 10G are waveform diagrams showing the control signal in FIG. 6 and the output signal controlled by the control signal.

[Explanation of symbols]

 1 magnetic head 2 magnetic head 3 recording amplifier 4 recording amplifier 5 magnetic head 6 magnetic head 7 reproducing amplifier 8 reproducing amplifier 9 bandpass filter 10 bandpass filter 11 demodulation circuit 12 demodulation circuit 13 bandpass filter 14 discrimination circuit

Claims (4)

[Claims] 1. A magnetic recording / reproducing apparatus which alternately switches two rotating magnetic heads to record and reproduce a carrier wave modulated based on a signal in an audio signal band, wherein a start end of a reproduced FM signal at the time of recording, A magnetic recording / reproducing apparatus characterized in that a discrimination signal for discriminating the content of an audio signal is recorded in a portion corresponding to the end. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the content of the audio signal is a stereo signal or a dual audio signal. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the reproduction FM signal and the discrimination signal are continuously extracted by a reproduction head switching pulse during reproduction. 4. The magnetic according to claim 1, 2 or 3, wherein one of two different carrier waves during recording is muted, and which carrier is muted during reproduction, and the content of the audio signal is determined. Recording / playback device.