KR870000850B1 - Stereo fm voice device - Google Patents

Abstract

This invention describes stereo FM device of 8mm magnetic recording and reviving device. two rotating sound heads are located in constant angle ( 0≰<alpha≰< 90≰) between first and second video tape so that stereo FM sound is recorded and revived in recorord and revival mode and it is possible to use mono FM sound device simultaneously. The used component of the invention are; Amp, noise-rejection device, FM modulator, carrier filter, mixer, envelope amp., free amp., alpha≰- shifter buffer, half-wave rectifiers switching circuit.

Description

Stereo FM audio device with 8mm magnetic recording and playback.

1 is a circuit diagram during recording according to the invention of the invention.

2 is a circuit diagram at the time of reproduction according to the present invention.

3 is a recording waveform diagram according to the present invention;

4 is a cross-sectional view of the head drum of the present invention.

5 is a video tape track state diagram according to the present invention.

6 is a video tape state diagram of the present invention.

7 is a circuit diagram of conventional recording and reproduction.

8 is a conventional recording waveform diagram.

9 is a conventional video tape track state.

10 is a state diagram of a conventional video tape.

*. Explanation of symbols for main parts of the drawings

1,6,18,29: Amplifier 2,7: Noise reduction encoder

3: main carrier FM modulator 4,13: FM main carrier pie

5: mixer 15,24: FM demodulator

8: subcarrier FM modulator 9,22: FM subcarrier filter

10: recording amplifier 12: composite signal envelope amplifier

14: main audio envelope amplifier 16,25: 14kHz regional pass filter

17,26: noise reduction decoder 23: negative envelope amplifier

11,20: preamplifier 19: switching circuit

21: buffer 27: half-wave distillation

28: comparator 30: α ° shuffler

VH1, VH2: First and second video heads AH1, AH2: Rotating voice head

A, B, C, A'C ': Signal input terminal SW1, SW2: Switch

VT: Video Tape HD: Head Drum

The present invention relates to a stereo FM audio device of an 8 mm magnetic recording and reproducing apparatus, in particular two rotations for a voice subcarrier at a constant angle (0 ° <α <90 °) between the first and second video heads in the head drum. The present invention relates to a stereo FM audio device of an 8mm magnetic recording and playback device in which stereo FM audio is recorded and reproduced at the time of recording and playback mode by using a voice head.

In general, in order to realize miniaturization and weight reduction in a magnetic recording and reproducing apparatus for recording and reproducing video and audio signals of a television on a video tape, a magnetic recording and reproducing apparatus using a high density video tape having a width of 8 mm is required. A β-type hi-fi video is adopted in which the signal is FM-modulated, mixed into a video FM signal, and recorded on the video tape by the rotating video head of the head drum. However, before the stereo FM audio device of the 8mm magnetic recording and playback device was used, it was used as a mono FM audio device as shown in FIG. 7, which was used for video and audio signals received by an antenna or a television broadcast. Recording and playback were done in 1) and (7-2).

To explain this, (7-1) of FIG. 7 is to record a mono FM audio and video FM signal on a video tape during recording mode, and the main audio signal is fed to the amplifier 1 through the signal input terminal A, and the video FM signal. The signals are respectively supplied to the mixer 5 through the video input terminal B, and the output signals are amplified by the main audio signal FM modulator 3 as the amplified main audio signals through the noise reduction coder 2. The modulated FM audio signal and the video FM signal from the video amplifier are mixed in the mixer 5, and the mixed signals are video taped as shown in FIG. 10 by the first and second video heads VH1 and VH2. On the magnetic layer M on the base film BF in VT, a luminance signal f + mono FM audio signal d + region conversion color signal b + tracking pilot signal d are recorded.

That is, a mono FM audio signal and a video FM signal are recorded on each track according to the operation of the first and second video heads VH1 and VH2 on the video tape VT. The pilot signal (a; f1-f4), the low frequency conversion color signal (b; fc), the FM main carrier signal (d; fA), and the FM luminance signal (f) are divided into a video signal (FD) The peak peak (WH ITE PEAK) and the sync signal tip (SYNCH-TIP) are shown as FM modulated.

Therefore, in order to reproduce the mono FM audio signal and the video FM signal recorded on the respective tracks shown in Fig. 9, the recording waveforms of Fig. 8 are operated by Fig. 7-2 of Fig. First, the mono FM audio signal and the video FM signal on the video tape VT picked up by the first and second video heads VH1 and V H2 in the head drum are combined through the preamplifier 11. ) Is supplied to the envelope amplifier 12 and a pulse frequency (D) of 30 Hz from the pulse generating servo is supplied to the preamplifier 11 and the FM demodulator 15, respectively, wherein the image FM signal through the composite signal envelope amplifier 12 Among the FM audio signals, the video FM signal is supplied to the video amplifier stage (E), and the FM audio signal is sequentially supplied to the main audio envelope amplifier 14 and the FM demodulator 15 of the FM main carrier filter 13. In the FM demodulator 15 supplied with the frequency D, the main voice The output signal of the envelope amplifier 14 is demodulated, and this demodulated audio signal is filtered out of the 14 kHz low pass filter 16.

Then, the above-described video FM signal is transmitted to the screen of the television receiver through the video amplifier stage, and the demodulated audio signal is sequentially transmitted to the outside through the noise reduction decoder 17 and the amplifier 18 so that the viewer can view it. .

The present invention is compatible with the mono FM audio device of the magnetic recording and reproducing apparatus used in the prior art, so that FM voice can be used as a mono channel and an FM voice subcarrier can be used as a stereo channel so that stereo can be heard. By installing two rotary voice heads for FM voice subcarriers at a certain angle (0 ° <α ° <90 °) between the second video heads, it is possible to record and play stereo FM voices on video tape during recording and playback mode. SUMMARY OF THE INVENTION An object of the present invention is to provide a stereo FM audio apparatus of an 8 mm magnetic recording and playback apparatus.

Hereinafter, the configuration, operation, and effects of the present invention will be described in detail with reference to the accompanying drawings.

According to the present invention, an amplifier (1), a noise reduction encoder (2), a main carrier FM modulator (3), and an FM main carrier filter (A) for amplifying minute signals sequentially in the signal input terminal (A) of the left channel into which the main audio signal is input 4) and the mixer 5, and the mixer 5 connects the video input terminal B to which the video FM signal is input and the first and second video heads VH1 and VH2 in the head drum HD;

The amplifier (6), the noise reduction encoder (7), the subcarrier FM modulator (8), and the FM subcarrier filter (9) are sequentially added to the signal input terminal (C) of the right channel to which the sub-audio signal for the stereo FM audio signal is input. And a rotary voice head AH1 and AH2 having a predetermined angle between the first and second video heads VH1 and VH2 through the recording amplifier 10.

The first and second video heads VH1 and VH2 are sequentially provided with a preamplifier 11, a composite signal envelope amplifier 12, an FM main carrier filter 13, a main audio envelope amplifier 14, and an FM demodulator. (15), 14kHz lowpass filter 16 and the noise reduction decoder 17 is connected, but the noise reduction decoder 17 is connected to the switch (SW1) of the amplifier 18 and the switching circuit 19,

The rotary voice heads AH1 and AH2 have an α ° shifter 30 and an FM demodulator 24 shifted by α ° through a preamplifier 20, and a preamplifier 11 to an α ° shifter 30. A 30 Hz pulse signal is connected to the FM demodulator 15, and the pre-amplifier 20 is sequentially supplied to the FM demodulator 24 through a buffer 21, an FM subcarrier filter 22, and a negative envelope amplifier 23. ) And half-wave rectifier (27), FM demodulator (24) via a 14 kHz low pass filter (25) and noise reduction decoder (26) to switch SW2 of switching circuit (10), half-wave rectifier (27). The switch SW1 (SW2) of the switching circuit 19 and the amplifier 29 are connected to the switching circuit 19 via the comparator 28, respectively.

Unexplained VT is a video tape, a and f1-f4 are tracking pilot signals b and fc are low-conversion color signals, d and fA are audio main carrier signals, f is FM luminance signal, FD is video signal, E is video amplifier, BF is the base film, M is the magnetic layer, e and fAS are the FM voice subcarrier signals, and Vp and Ap are the video and voice track pitches.

FIG. 1 is a circuit tool diagram of a recording mode according to the present invention. As shown in FIG. 4 to record a video FM signal and a stereo FM audio signal of a television on a video tape (VT), FIG. It is made by the operation of the head drum HD in which a rotary voice head AH1 (AH2) is constituted for the FM voice subcarrier at a constant angle (0 ° <α ° <90 °) between the heads VH1 and VH2. . Therefore, the FM audio subcarrier signal e between the FM audio main carrier signal D and the FM luminance signal f in the conventional recording method shown in FIG. 8 to realize a video FM signal and a stereo FM audio signal of a television. Is set as shown in FIG. 3, which is a tracking pilot signal (a; f1-f4), a low frequency shift color signal (b; fc), an FM main carrier signal (d; fA), and an FM voice subcarrier signal (e; fAS). ) And the FM luminance signal (f), and the video tape (VT) records the FM voice subcarrier signal (fAS) in the magnetic layer (M) on the base film (BF) as shown in FIG. The signal (f) + FM main carrier signal (d) + region conversion color signal (b) + tracking pilot signal (a) are recorded.

As described above, in order to record a video FM signal and a stereo FM audio signal of a television on a video tape, a main audio signal is input at the signal input terminal A of the left channel, and a negative audio signal is output at the signal input terminal C of the right channel. (6), each of the amplified voice signals is shaped by a noise reduction encoder (2) (7), and the primary carrier FM filter (4) and the primary carrier FM filter (4) through the primary carrier FM modulator (3) and the subcarrier FM modulator. The FM subcarrier filter 9 is supplied to the mixer, and the FM main carrier signal fA through the FM main carrier filter 4 is supplied to the mixer 5, so that the mixer 5 has an image through the video input B. The magnetic layer of the video tape VT of FIG. 6 on each track shown in FIG. 5 by the first and second video heads VH1 and VH2 in the head drum HD by mixing the FM signal and the FM audio signal. Recorded in (M). In addition, the FM voice subcarrier signal fAS through the FM voice subcarrier filter 9 is amplified by the recording amplifier 10 so that a constant angle (0 ° <α ° <) between the first and second video heads VH1 and VH2 is obtained. 90 °) is similarly symmetrical on the angular track shown in FIG. 5 by the rotary voice heads AH1 and AH2, which are recorded in depth in the magnetic layer M of the videotape VT as in FIG.

On the other hand, the azimas recording of the rotary voice head AH1 (AH2) for the FM voice subcarrier between the first and second videos VH1 and VH2 in the head drum HD is shown in FIG. As shown in FIG. 5, the azima format of the first and second video heads VH1 and VH2 is defined as 10 °, and the present invention is defined as β ° of the rotary voice head AH1 and AH2 as 15 ° as shown in FIG. At -70 °, audio and video track pitch (AP) can be used arbitrarily in the range of several micrometers to several tens of micrometers, and azimas can be used to eliminate cross-talk between video and audio signals. Record to cross each other.

The deeply recorded FM audio subcarrier signal fAS and FM luminance signal f + FM audio main carrier signal d + low-conversion color signal b + tracking pilot signal a are recorded by the above operation. It is recorded in each track shown in FIG., Which is operated by the circuit configuration as shown in FIG. 2 when the playback mode is selected to reproduce the recorded video FM signal and stereo FM audio signal.

That is, the FM audio signal and the video FM signal picked up by the first and second video heads VH1 and VH2 in the head drum HD are the preamplifier 11 and the first and second video heads VH1. The FM voice subcarrier signals picked up by the rotary voice heads AH1 and AH2 at a constant angle between (VH 2) are supplied to the preamplifier 20, respectively, and a pulse frequency D of 30 Hz is generated by the pulse signal generating servo. ) Is supplied to the preamplifier 11, the FM demodulator 15, and the α ° shifter 30, respectively, wherein the signal shifted by α ° through the α ° shifter 30 is transferred to the preamplifier 20 and the FM demodulator ( 24) respectively. First, the FM audio signal passing through the composite signal envelope amplifier 12 through the pre-amplifier 11 is supplied to the FM main carrier filter 13, and the video FM signal is supplied to the video amplifier E, respectively. After the filter is filtered by the FM main carrier filter 13, it is amplified by the main audio envelope amplifier 14 and supplied to the FM demodulator 15. In the FM demodulator 15 supplied with a pulse frequency of 30 Hz, the main audio envelope amplifier The output signal of (14) is demodulated and then filtered by the 14 kHz lowpass filter 16 and supplied to the amplifier 18 and the switch SW1 of the switching circuit 19 through the noise reduction decoder 17.

Meanwhile, the FM audio subcarrier signal picked up by the rotary voice heads AH1 and AH2 at a predetermined angle between the first and second video heads VH1 and VH2 is amplified by the preamplifier 20 and the buffer 21. The FM voice carrier signal passed through the buffer 21 and filtered through the FM voice carrier and the filter 22 is then amplified by the negative envelope amplifier 23 to be supplied to the FM demodulator 24 and the half wave rectifier ( 27), and the FM demodulator 24, which is shifted by α ° from this and supplied with a pulse frequency D of 30 Hz, is demodulated with an output signal of the negative envelope amplifier 23, and then the 14 kHz low pass filter 25 And is supplied to the switch SW2 of the switching circuit 19 through the noise reduction decoder 26.

In addition, the signal through the half-wave rectifier 27 is compared by the comparator 28 to select whether to reproduce a mono FM audio signal or a stereo FM audio signal. First, an output signal (0.1) state of the comparator 28 is selected. In this case, the stereo FM audio signal is reproduced. That is, since the output signal of the comparator 28 in the state (0.1) is applied to the switches SW1 and SW2 as the control signal of the switching circuit 19, the switch SW1 is turned off and the switch SW2 is turned on to reduce the noise. (26) through the negative signal amplifier 29 to the output terminal (C ') of the right channel, the main audio signal through the amplifier 18 to the output terminal (A') of the left channel, and the video FM Since the signal is transmitted through the video amplifier (E), the video FM signal recorded on the video tape (VT) and the stereo FM audio preferences are reproduced so that the viewer can watch the stereo through the TV receiver.

On the other hand, when the output signal of the comparator 28 is (1.0) state, the mono FM audio signal is reproduced. This means that the signal applied to the switch SW1 (SW2) of the switching circuit 19 is the (1.0) state of the control signal. The switch SW1 is turned on and the switch SW2 is turned off to block the negative audio signal of the rotary voice heads A H1 and AH2. The main audio signal described above is output through the amplifier 18 at the output terminal of the left channel ( A ') and the video FM signal are reproduced through the video amplifier stage E so that only the video signal and the main audio signal are reproduced by the television receiver.

As described above, the present invention provides two rotary voice heads for the FM voice subcarriers at a predetermined angle (0 ° <α ° <90 °) between the first and second video heads of the head drum in the 8 mm magnetic recording and reproducing apparatus. It can be used as a mono FM audio device at the same time as recording and playback mode.

Claims (2)

An amplifier (1), a noise reduction encoder (2), a main carrier FM modulator (3), an FM main carrier filter (4), and a mixer that sequentially amplify minute signals to the signal input terminal (A) of the left channel to which voice signals are input. (5), and the mixer 5 connects the video input terminal B to which the video FM signal is input and the first and second video heads VH1 and VH2 in the head drum HD. The amplifier 6, the noise reduction encoder 7, the FM modulator 8, the FM subcarrier filter 9 and the recording amplifier are sequentially added to the signal input terminal C of the right channel to which the FM audio signal for the stereo FM audio signal is input. The rotary voice heads AH1 and AH2 of a predetermined angle are connected between the first and second video heads VH1 and VH2 through 10. The first and second video heads VH1 and VH2 are sequentially provided with a preamplifier 11, a composite signal envelope amplifier 12, an FM main carrier filter 13, a main audio envelope amplifier 14, and a demodulator ( 15), 14kHz low pass filter (16) and noise reducer (17) is connected to the noise reduction decoder (17), the amplifier (18) and the switch (SW1) of the switching circuit (19), The rotary voice heads AH1 and AH2 have an α ° shifter 30 and an FM demodulator 24 shifted by α ° through a preamplifier 20, and an α ° shifter 30 has a preamplifier 11. The FM demodulator 15 and the pre-amplifier 20 are sequentially supplied to the FM demodulator 24 and the half-wave rectifier through the buffer 21, the FM subcarrier filter 22, and the sub-envelope envelope amplifier 23. 27), the FM demodulator 24 is connected to the switch SW2 of the switching circuit 19 via a 14 kHz lowpass filter 25 and a noise reduction decoder 26, and a comparator 28 to the half-wave rectifier 27. 8 mm magnetic recording reproduction for recording and reproducing stereo FM audio during recording and playback mode by connecting switches SW1 and SW2 of the switching circuit 19 and the amplifier 29 to the switching circuit 19, respectively. Stereo audio device of the device. The FM voice subcarrier (fAS) band is an arbitrary band set between the FM audio main carrier band and the FM luminance band for recording and reproducing a stereo FM audio signal.

Images