JPH0557799B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an azimuth-type video signal magnetic recording and reproducing apparatus that forms video signals suitable for dubbing.

Conventional technology Video signal magnetic recording and reproducing device (hereinafter referred to as VTR)
has an antenna input terminal 1 for receiving television broadcast waves as shown in Fig. 1, and a video signal and an audio signal are respectively detected from the received television broadcast waves, and the brightness signal of the video signal is FM modulated. At the same time, the color signal is converted to a low frequency and recorded, and the audio signal is directly recorded using an AC bias method. On the other hand, during playback, the reproduced video signal is separated into an FM luminance signal and a low frequency converted color signal, and the FM brightness signal is demodulated and the low frequency converted color signal is returned to its original frequency before being mixed and reproduced. The received audio signal is RF-modulated and output to the antenna output terminal 2 as the same as a television broadcast wave. In other words, this antenna output terminal 2 usually has a second channel (or a first channel).
Since an equivalent television signal _S''1 is output, this signal can be received at the antenna terminal of the television receiver and the video can be monitored. Line video input terminal 3 for inputting and outputting cameras, etc.
, a line audio input terminal 5 , a line video output terminal 4 , and a line audio output terminal 6 . As for the line video input terminal 3 and the line video output terminal 4 for video, the video signal itself, that is, the signal that has not been processed for RF modulation or recording, is input and output, and the line audio input terminal 5 and the line video output terminal 4 for audio are input and output. The audio signal itself is input and output to the line audio output terminal 6.

Prepare two VTRs like the ones above, and connect the playback side VTR.
7 and the recording side VTR 7'.The easiest way to do this is to dub the recording side VTR 7' as shown in
Antenna output terminal 2 of VTR7 and recording side VTR7'
Connect the antenna input terminal ₁ ' of the
7's line video output terminal 4 and line audio output terminal 6 are connected to the line video input terminal 3' and audio input terminal 5' of the recording side VTR 7' with Y, Y, Y', Y', respectively, to output a video signal. It may also input and output audio signals. In other words, the video reproduction system of a VTR includes a luminance signal reproduction system and a color signal reproduction system, and the color signal reproduction system, as shown in _FIG . low pass filter 1
Enter 0. Passed through low pass filter 10
688kHz reproduction low frequency conversion color signal S ₂ is ACC11,
Frequency converter 1 that converts using a 4.27MHz conversion carrier wave
2 and a bandpass filter 13 with a center frequency of 3.58 MHz, and is input to a comb filter 14 as a reproduced color signal S' ₂ . The recorded color video signal recorded on the magnetic tape 15 forms a track pattern of video tracks T ₁ , T' ₁ , . . . T _o , T' _o for one frame of one set of two fields as shown in FIG. and is tracked by the video head 8 in the direction of the arrow a. The recording low-frequency conversion color signal is recorded with the phase reversed by 180 degrees every horizontal scanning line (hereinafter referred to as 1H) in video track _T1 , and recorded without reversing the phase in video track _T'1 of the next field. Repeat alternately. The comb filter 14 removes crosstalk signals from adjacent tracks by combining the reproduced color signal _S'2 through the 1H delay line and the undelayed reproduced color signal _S'2 . The reproduced color signal S″ ₂ from which the crosstalk signal has been removed is mixed with the reproduced luminance signal S′ ₃ demodulated by the mixer 16 and output as the reproduced video signal S′ ₁ via the output terminal 17. It is supplied from the line video output terminal 4 to the line video input terminal 3' of the recording side VTR 7', and dubbing is performed.The reference numeral 18 in FIG.
20 is a high-pass filter that passes the FM luminance signal; 21 is an FM demodulator; _H is the horizontal synchronization signal.

Problems with the Prior Art In the dubbing method described above, in particular, the video signal system passes through various filters and waveform shaping is performed, so the image quality deteriorates rapidly with repeated dubbing. To prevent this image quality deterioration, industrial VTRs have a method of directly outputting the signal _S1 , which has been played back by the video head and amplified by the preamplifier, to the recording video head, but home VTRs that use the guard bandless recording method Since the crosstalk signal from the adjacent track is played back at a considerable level, if you dub it as is, the crosstalk component will be recorded on the tape with a one field shift, which cannot be canceled out during playback, resulting in wow and flutter. A beat occurs.

OBJECTS OF THE INVENTION An object of the present invention is to provide a video signal magnetic recording and reproducing apparatus having a color signal reproducing system for reproducing color video signals suitable for dubbing.

Structure of the Invention The present invention provides reproduction low-pass conversion using a comb filter including a variable delay element driven by a pulse whose frequency varies in proportion to the jitter component of a reproduction low-pass conversion color signal separated from a reproduction video signal. configuring a noise removal signal for removing jitter in the chrominance signal and crosstalk signals from adjacent tracks; The separated reproduced low frequency conversion color signal and luminance signal are combined,
The obtained reproduced video signal is suitable for dubbing.

Embodiment of the Invention An embodiment of the video signal magnetic recording and reproducing apparatus of the present invention will be described in detail with reference to the drawings.

In FIG. 4, the same parts as in FIG. 2 are denoted by the same reference numerals, so their explanation will be omitted.

In FIG. 4, reference numeral 22 denotes a phase inverter, in which the reproduced low-pass converted color signal S 2 obtained by separating the reproduced color video signal S ₁ reproduced by the video head ₈ by the low-pass filter 10 is brought to a constant level by the ACC 11. is input. The reproduced low-frequency converted color signal S ₂ undergoes phase inversion in accordance with the inversion pulse 〓 by the phase inverter 22, and the portion inverted during recording is returned to its original state and output to the comb filter 23. In the conventional color signal reproducing system shown in FIG. 2, by inverting the corresponding phase of the 4.27 MHz converted carrier wave of the frequency converter 12, the inverted phase when recording the reproduced low frequency converted color signal _S2 is inverted.

The comb filter 23 has an input terminal 23a, an output terminal 23b, and a clock terminal 23c.
It operates with the clock pulse _C supplied from the APC/AFC 25 to the clock terminal 23c, and the input terminal 23
Jitter and crosstalk signals are removed from the low frequency converted color signal _S2 inputted to a, and the result is outputted to an output terminal 23b. The outputted low frequency converted color signal S ₂ is input to the phase inverter 24 and the frequency converter 12 .

The comb filter 23 has an angle of 90° as shown in FIG.
The reproduced low frequency conversion color signal S ₂ formed by the phase shifter 26 and the CCD unit 27 and input to the input terminal 23 a of the comb filter 23 is transmitted via the input pin 27 a of the CCD unit 27 and the 90° phase shifter 26 . It is input to input pin 27b.

The CCD unit 27 is composed of a 1-bit CCD 28, a 351-bit CCD 29, a clock driver 30, an arithmetic unit 31, and an output amplifier 32. CCD
The unit 27 operates by supplying the 5.5 MHz clock pulse _C output from the 350 _H VCO 33 provided in the APC/AFC 25 shown in FIG. 6 to the clock driver 30 via the clock terminal 23c and the clock pin 27d. The output of the 351-bit CCD 29 is sequentially subtracted from the output of the 1-bit CCD 28 in the arithmetic unit 31, and the result is outputted via the output pin 27c and the output terminal 23b.

The 90° phase shifter 26 is connected to a resistor R, as shown in FIG.
There are three sets of circuits each including R', capacitors C and C', and an operational amplifier IC, resulting in a three-stage configuration.

In the APC/AFC 25 shown in FIG. 6, the color signal output from the bandpass filter 19 is input to the terminal 25a, and based on the burst signal, a signal whose phase is locked to the burst signal is created in the APC loop of the circuit 36, Controls each part.
350 _H The frequency of the VCO is the frequency of the horizontal sync signal _H.
350 times, which is 8 times the frequency of the reproduced low-frequency conversion color signal _S2 . Therefore, the integer 350 is obtained from the frequency of the horizontal synchronizing signal _H and the center frequency of the reproduced low-frequency conversion color signal _S2 , which is a substantially appropriate bit for the number of stages of the CCD delay element. Note that the frequency of the clock pulse _C must be at least twice the upper limit of the signal band due to the limit of the Nyquist frequency, which is defined as a frequency that is 1/2 of the frequency of the clock pulse _C. The center frequency of the reproduced low-pass conversion color signal _S2 is
Since the frequency of the clock pulse C is 688 kHz (43.75 times the frequency of the horizontal synchronizing signal _H ) and the signal band is 1.3 MHz to 2.6 MHz, the frequency of the clock pulse _C of 5.5 MHz satisfies the condition of the Nyquist limit. Further, since the ordinary comb filter 14 is used in the 3.58 MHz band, the frequency of the clock pulse _C ' is 10.7 MHz. Therefore, the delay line used in the CCD unit 27 of the present invention has a small number of bits, and the frequency of the clock pulse _C is approximately half that, 5.5 MHz, thus successfully reducing power consumption significantly.

The respective numerical values in this embodiment are not limited to these.

350 _H with APC/AFC25 frequency converter 34
Obtained by dividing VCO33 frequency 5.5MHz by 1/8
4.27MHz is created by adding 688kHz and 3.58MHz of the 3.58MHz crystal oscillator 35. This 4.27MHz is used as the idler of frequency converter 12, and the 688kHz
The reproduced low frequency conversion color signal S ₂ is converted into the reproduced color signal S′ ₂ of 3.58 MHz.

The phase inverter 24 converts the reproduced low frequency converted color signal S ₂ inputted from the comb filter 23 into APC/AFC 25
It is inverted in response to the inversion pulse S 2 outputted from the terminal 25c of , and outputs the reproduced low-frequency converted color signal S ₂ to the mixer 16'. Therefore, at the output of the phase inverter 24,
The phase of the part that was phase-inverted during recording is phase-inverted again,
It is mixed with the reproduced FM luminance signal S ₃ by a mixer 16' and outputted from an output terminal 17' as an RF video signal S ₁ for dubbing. Playback side VTR7 and recording side VTR
7', one frame consists of a set of two fields, so it is necessary to synchronize in units of one frame.
Since this synchronization signal can be easily obtained from the video head switching pulse of the reproducing side VTR 7, the rotational servo circuit of the recording system of the recording side VTR 7' is initialized by this head switch pulse RF _SW . Reproduction low frequency conversion color signal without phase inversion
_S'2 is passed through a frequency converter 12 and a 3.58MHz bandpass filter 19 as a reproduced color signal _S''2 , which is mixed with a reproduced luminance signal _S'3 by a mixer 16 and outputted as a reproduced video signal S through an output terminal 17. ′ _1. This reproduced video signal S′ ₁ can be used for monitoring.

FIG. 7 is a detailed block diagram of the APC/AFC 25 portion of FIG. 4. In the APC/AFC 25', the inverted pulse of the phase inverter 22 described above is formed in accordance with the head switch pulse RF _SW generated by the servo circuit. The output of the 1/2 frequency divider 37 of the horizontal synchronizing signal _H is converted into a head switch pulse by the gate 38.
It opens and closes using the RF _SW to obtain an inverted pulse that inverts every other field and every 1H. The color signal taken out from the bandpass filter 19 and the output of the 3.58MHz crystal oscillator 39 are phase-compared in a phase comparator 40 for only the period of the burst signal included in the color signal, and the phase of the 3.58MHz crystal oscillator 41 is determined by the phase of the reproduced burst signal. Locks on phase. The frequency converter 42 acts as an idler for the frequency converter 12 according to the output of the phase-locked 3.58MHz crystal oscillator 41.
4.27MHz is outputted via the bandpass filter 42a. Phase comparator 43 receiving horizontal synchronization signal _H
is the loop of VCO 44 and 1/m frequency divider 46.
Locks the frequency of VCO 44 and 1/n frequency divider 45
688kHz is outputted to the frequency converter 42 via.

FIG. 8 is another example of FIG. 7, and is the same as FIG. 7 except that the VCO 44 is controlled by the digital AFC 47.

When reproduction is performed, the reproduced low frequency converted color signal S ₂ output from the phase inverter 22 is passed through the comb filter 23
is input. The reproduced low frequency conversion color signal _S2 has the reverse phase of the video track _T1 shown in FIG. 3 every 1H inverted by a phase inverter 22. The 688kHz reproduced low-frequency conversion color signal S ₂ is the frequency of the horizontal synchronization signal _H.
It is 43.75 times, not an integer multiple, but shifted by 1/4・_H. For this reason, in the conventional comb filter 14, crosstalk signals cannot be completely removed because the peaks or valleys are integer multiples or in between. Since there is a 90° phase difference between the n-th line and the n-1 horizontal scanning line, a comb filter can be configured by shifting the phase by 90° across the entire signal band and then inputting it to the delay line. I can do it. Therefore, in the comb filter 23 of the present invention, a 90° phase shifter 26 is inserted between one input pin 27b of the CCD unit 27 and the input terminal 23a, so that the phase shifter 26 is inserted between the input pins 27a and 27b. , so that the valleys do not overlap. The 90° phase shifter 26 shows 5.7° at points a and b of the curve h in FIG. 10 in the range of 688kHz±500kHz, and there is little phase shift from 90° over almost the entire range.
Crosstalk signals are thus completely removed.

Effects of the Invention The video signal recording and reproducing apparatus of the present invention includes a pulse generating means for obtaining a clock pulse proportional to the carrier frequency of the reproduced low-frequency conversion color signal, and a comb-shaped delay line whose delay time changes according to the clock pulse. Because it is configured with a filter,
Compared to conventional comb filters using delay lines in which the delay time does not change, this filter has the advantage of being able to remove crosstalk signals over the entire frequency band of low-band converted color signals.

In addition, since the configuration is equipped with a phase shift means for interleaving the low frequency converted color signal from which the crosstalk signal has been removed and the low frequency converted color signal related to the adjacent video track, the low frequency converted color signal processed by the phase shifting means is It has the feature of being able to mix the FM luminance signal and the FM luminance signal to form a color video signal for dubbing. Therefore, even if recording and playback are performed repeatedly, high-quality images can be obtained. Furthermore, since a comb filter for removing crosstalk signals is provided before the low frequency conversion color signal is processed by the phase shifting means, the Nyquist frequency of the delay line can be reduced to less than half of the conventional one.

In addition, since it is configured to include a pulse multiplier means for multiplying the horizontal synchronizing signal frequency to obtain the clock pulse, and a comb filter is driven by the clock pulse obtained by the pulse multiplier means to remove crosstalk of the low frequency conversion color signal, it is possible to reproduce the color signal. It has the advantage of being able to easily remove jitter from color video signals. Therefore, it is possible to omit various conventional circuits related to phase fluctuations due to jitter and the like.

In addition, since it is configured to include a variable frequency oscillator of an APC loop that synchronizes the phase of the burst signal obtained from the color signal converted to the original frequency and the reference signal related to the frequency conversion means for forming the idler signal, It has the advantage that the clock pulse can be formed from the oscillation output of this variable frequency oscillator. Therefore, color phase fluctuations are immediately corrected, the response to disturbances is accelerated, and a stable reproduced color signal can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional dubbing method, Fig. 2 is a block diagram of a conventional color video signal magnetic recording/reproducing device, Fig. 3 is an illustration of a recording pattern of a video track on a magnetic recording/reproducing medium, and Fig. 4 is a diagram of a recording pattern of a video track on a magnetic recording/reproducing medium. A block diagram of an embodiment of the video signal magnetic recording and reproducing device of the present invention,
Figure 5 is a block diagram of the comb filter shown in Figure 4.
Figure 6 is an explanatory diagram of APC/AFC in Figure 4, Figure 7 is a detailed block diagram of APC/AFC in Figure 6, and Figure 8 is a detailed block diagram of APC/AFC in Figure 6.
This figure is a block diagram of another example of FIG. 7, FIG. 9 is a block diagram of a 90° phase shifter provided in the comb filter of FIG. 5, and FIG. 10 is a characteristic diagram of FIG. In the figure, 11 is an ACC, 22 and 24 are phase inverters, 23 is a comb filter, 12 is a frequency converter, 19 is a bandpass filter, 25, 25',
25'' is APC/AFC, 44 is VCC, and 47 is digital AFC.

[Claims]

1. A group of keys respectively assigned to one of two or more electronic entertainment devices, and an instruction code that is activated by activation of a control element of the group of keys and is retrieved from the instruction code memory in response to activation of the control element. In an entertainment device system comprising two or more entertainment electronic devices comprising a remote control transmitter comprising a remote control circuit operative to form a remote control signal containing remote control instructions, one of said keys and a plurality of additional data memories, each storing data for program execution of a corresponding one of the plurality of different remote control transmission systems; a plurality of additional command code converters, each generating a command code corresponding to an energized control element of a key group of a corresponding one of the plurality of different remote control transmission systems; it to operate in conjunction with at least one of each one of the instruction transcoding devices and each corresponding additional data memory;

Claims (1)

and output means for supplying the output of the addition means to a recording means different from the recording means for recording on a recording medium different from the magnetic recording medium. Recording and playback device.