JP2962567B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus for magnetically recording and reproducing a video signal, and more particularly to a color signal recording circuit thereof.

Conventional technology The typical carrier chrominance signal frequencies are 3.58MHz used mainly in the NTSC system and 4.43MHz used mainly in the PAL system.
There are two types of systems. 2. Description of the Related Art Among magnetic recording / reproducing apparatuses, there is a multi-system magnetic recording / reproducing apparatus capable of magnetic recording / reproducing both of these methods.

A color signal recording circuit of a conventional VHS multi-system magnetic recording / reproducing apparatus will be described with reference to the drawings.

The color signal recording circuit of the conventional VHS multi-method magnetic recording / reproducing apparatus shown in FIG. 2 has 3.58 MHz NTSC, 4.43 MHz NTSC, PAL, M
−PAL, N-PAL color signal recording circuits 22, 23, 24, 25,
26.

Input color signals are 3.58MHz NTSC, 4.43MHz NTSC, PA
L, M-PAL, N-PAL color signal recording circuits 22, 23, 2
4, 25, 26, the recording circuit that matches the inputted color signal operates, the output signal of the color signal recording circuit is selected by the selection circuit 27, and mixed with the input modulated luminance signal by the mixing circuit 12. Thereafter, the recording signal is input to a head via a recording amplifier and recorded.

The color signal recording circuit of the conventional VHS multi-method magnetic recording and reproducing apparatus shown in FIG. 3 realizes multi-method recording by switching a part of the color signal recording circuit.

The input carrier color signal a is input to a 3.58 MHz band pass filter (BPF) 1 and a 4.43 MHz BPF 9,
In the case of 3.58MHz NTSC, M-PAL, N-PAL system (3.58M
Hz signal) the color signal carrier frequency is 3.58MHz
When the output signal of BPF1 is 4.43MHz NTSC or PAL (because it is a 4.43MHz system signal) because of z, the output signal of BPF9 is selected because the carrier frequency of the color signal is 4.43MHz. The selected signal is supplied to the frequency conversion circuit 10 and the 3.58 MHz NTS
APC circuits 29, 30, 31, 32 for C, PAL, M-PAL and N-PAL systems
Is input to

Each of the APC circuits 29, 30, 31, and 32 extracts a burst signal from the color signal b selected by the selection circuit 28, compares this with a signal from a crystal oscillator in the circuit, and adjusts the phase for each burst signal. The frequency of the crystal oscillator is finely adjusted, and a continuous signal c synchronized with the burst signal is output. But these APCs
Since the circuit uses a crystal oscillator, the frequency cannot be varied greatly. Even though it is the same 3.58MHz system, NTSC system is 3579545Hz, M-PAL system is 3575611.49H
Since the frequency of the z, N-PAL system is slightly different from 3582056 Hz, the crystal oscillator is 443 of the 4.43 MHz NTSC / PAL system.
Four types are required in addition to those of 3618.75Hz. The output signal of each of the APC circuits 29, 30, 31, and 32 is selected by the selection circuit 33 according to the carrier frequency of the color signal, and is input to the frequency conversion circuit 14.

On the other hand, the horizontal synchronizing signal d of the frequency fh included in the luminance signal
Is input as a reference signal to a phase comparison circuit 20. The phase comparison circuit 20, a low-pass filter (LPF) 19, a voltage controlled oscillator (VCO) 18, and a frequency dividing circuit 21
For the 4.43MHz NTSC system, 320 times the frequency fh, PAL, MP
In the case of the AL, N-PAL system, an oscillation signal e having a frequency of 321 times the frequency fh is output. This oscillation signal e passes through a 1/2 frequency dividing circuit 17 and a rotary circuit 16, and as a result, a 3.58 MHz NTS
C, in case of 4.43MHz NTSC system, 40 times frequency fh, PAL, M
In the case of the −PAL or N-PAL method, an oscillation signal g having a frequency (40 + 1/8) times the frequency fh is input to the frequency conversion circuit 14,
From the continuous signal c of the frequency fsc of the selection circuit 33, 3.58 MHz NT
SC, 4.43MHz NTSC frequency fsc + 40fh, PAL,
Frequency fsc + (40 + 1/8) for M-PAL and N-PAL systems
A signal of fh is formed, input to the 5.06 MHz BPF 15 and the 4.21 MHz BPF 34, and unnecessary components generated in the frequency conversion circuit 14 are removed. Then, in the selection circuit 35, 3.58 MHz NTSC, M-PAL,
In the case of N-PAL system, the output signal of 4.21MHz BPF34 is 4.43M
In the case of the HzNTSC or PAL system, an output signal of 5.06 MHz BPF15 is selected, and the selected signal i is input to the frequency conversion circuit 10. In the frequency conversion circuit 10, the color signal b of the carrier frequency fsc of the selection circuit 28 is mixed with the signal i of the selection circuit 35, and in the case of the 3.58 MHz NTSC or 4.43 MHz NTSC system, the frequency 40 is used.
fh, PAL, M-PAL, N-PAL system frequency (40 + 1
/ 8) Modulated to color signal j. At fh carrier frequency, 16MHzL
Input to PF11. Unnecessary components generated in the frequency conversion circuit 10 are removed by the LPF 11, mixed with the input converted luminance signal k by the mixing circuit 12, and thereafter, the recording signal 1 is input to the head via the recording amplifier and recorded.

However, the configuration of the conventional magnetic recording / reproducing apparatus shown in FIG. 2 requires dedicated color signal recording circuits 22, 23, 24, 25, and 26 for each system, and the circuit scale is large. In addition, cost increases,
In the configuration shown in FIG. 3, two for 3.58 MHz and 4.43 MHz are used.
System filters 1, 9, 15, and 34, and a crystal oscillator for each system and its selection circuit 33 are required, which complicates the circuit and makes it difficult to perform standard design with magnetic recording / reproducing devices other than multiple systems. was there.

The present invention solves the above problem, and converts the carrier color frequency of a color signal into a frequency that can be processed by the color signal recording circuit before the color signal recording circuit, so that the color signal reproduction circuit It is an object of the present invention to provide a magnetic recording / reproducing apparatus in which switching between a filter and a crystal oscillator is eliminated, a circuit size is reduced, and cost is reduced.

Magnetic recording and reproducing apparatus of the present invention for solving the means above problems to solve the problem, at least one oscillator oscillating frequency is f _1,
A frequency converter for outputting a frequency carrier chrominance signal of the sum or difference of the output signal and the input carrier chrominance signal and a multiplying two signals of the frequency f ₁ from the oscillator, the input carrier chrominance signal or said frequency converter the carrier chrominance frequency conversion circuit composed of a selection circuit for selecting an output signal output, prepends color signal recording circuit for processing the input carrier chrominance signal of frequency f _2, the carrier chrominance signal of frequency f ₂ , the frequency f ₁ + f ₂ or frequency, | is to record at least one carrier chrominance signal of the carrier chrominance signal of | f ₂ -f _1.

By the action above configuration, the oscillator and in the carrier chrominance frequency converting circuit composed of a frequency converter and a selection circuit, by the color signal recording circuit for converting the carrier chrominance frequency which can be processed, the carrier chrominance signal of frequency f _2, Frequency f ₁ + f ₂ or frequency | f ₂
At least one of the carrier color signals of −f ₁ | is easily recorded with a smaller circuit size and lower cost than in the past.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The same components as those in FIG. 3 of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows the frequency f2 in one embodiment of the present invention as 4.
FIG. 11 is a block diagram of a magnetic recording / reproducing apparatus that records a carrier color signal of a 43 MHz system and a carrier color signal of a 3.58 MHz system as a frequency | f2-f1 |.

The color signal recording circuit of the magnetic recording / reproducing apparatus shown in FIG.
MHz NTSC system, PAL system color signal recording circuit, that is, the conventional 4.43MHzBPF9, frequency conversion circuits 10, 14, 1.6MHz LPF11,
Mixing circuit 12, APC circuit 13 with frequency 4433619Hz, 5.06MHz BPF
15, rotary circuit 16, 1/2 frequency divider circuit 17, VCO18, LPF1
9. A carrier color frequency conversion unit (circuit) 8 for converting a 3.58 MHz system to a 4.43 MHz system signal is added before the color signal recording circuit including the phase comparison circuit 20 and the frequency dividing circuit 21. It enables recording of 3.58 MHz NTSC, M-PAL, and N-PAL color signals.

Carrier color frequency converter 8 from 3.58MHz system to 4.43MHz system
Is a frequency conversion circuit 2 for multiplying a 3.58 MHz BPF1, a 3.58 MHz system signal and a reference signal m, and performing frequency conversion.
A selection circuit 7 for selecting a system signal and a 4.43 MHz system signal, a 3.58 MHz NTSC oscillator 3, an M-PAL oscillator 4, and an N-PAL oscillator 5 for oscillating the reference signal m, and a selection for selecting the reference signal m It comprises a circuit 6.

In FIG. 1, first, the input carrier color signal a is 3.58
A case where the signal is a MHz NTSC signal will be described.

The 3.58 MHz NTSC signal is input to the frequency conversion circuit 2 via the 3.58 MHz BPF 1. On the other hand, a 3.58MHz NTSC oscillator (frequency is the difference between carrier color frequencies, 854074Hz
The frequency conversion circuit 2 converts the 3.58 MHz NTSC signal into a 4.43 MHz NTSC signal n, which is selected by the selection circuit 7 and output as a 4.43 MHz color signal a '. The selection circuit 7 is a 4.43MHz NTSC
In the case of the color signal of the PAL system, the input carrier color signal a is output as it is as a color signal a '.

Similarly, when a signal of the M-PAL system is input, the selection circuit 6 generates an M-PAL oscillator (frequency: 858008 Hz (44333619-3).
575611Hz)) 4 reference signals m are selected and 4.43MHz M
-Converted to PAL signal and output.

Further, when a signal of the N-PAL system is inputted, the N-PAL oscillator (frequency: 851563 Hz (44333619)
−3582056Hz)) Five reference signals m are selected and 4.43MHz
It is converted to a PAL signal and output.

The carrier color frequency converter 8 converts the 3.58 MHz signal to a 4.43 MHz signal and outputs the resulting color signal a ′.
Is modulated by a conventional color signal recording circuit into a recording signal in the same manner as in the conventional example, and the recording signal 1 is input to a head via a recording amplifier and recorded.

In this embodiment, the recording circuit of the 4.43 MHz system is used as a base, but the same can be applied to a recording circuit of a 3.58 MHz system. At this time, a 3.58 MHz BPF1 (FIG. 3) replaces the 4.43 MHz BPF9 of FIG. 1, an APC circuit 29 of frequency 3579575 Hz instead of the APC circuit 13 of 4343319 Hz (FIG. 3),
A 4.21 MHz BPF34 (FIG. 3) is used in place of the 5.06 MHz BPF5.
BPF9 of 4.43 MHz (FIG. 3) in place of PF1, oscillator for 3.58MHz NTSC, oscillator for M-PAL 4, oscillator for N-PAL 5, and oscillator for 4.43MHz NTSC (PAL) in place of selector circuit 6 (frequency) Is the frequency of the difference between the carrier color frequencies; 854074 Hz (44336
19-3579545 Hz).

According to such a configuration, the input carrier color signal a
4.43MHzNTS for 4.43MHzNTSC signal (or PAL signal)
The C (or PAL signal) is input to the frequency conversion circuit 2 via the 4.43 MHz BPF 9, and the signal from the 4.43 MHz NTSC (PAL) oscillator is converted to the 3.58 MHz NTSC signal n in the frequency conversion circuit 2 used as the reference signal m. Is selected by the selection circuit 7 and output as a 3.58 MHz color signal a '. Selection circuit 7
Outputs the input carrier color signal a as it is in the case of a 3.58 MHz NTSC color signal. The color signal a ′ converted from the 4.43 MHz signal to the 3.58 MHz signal in the carrier color frequency conversion number 8 and output by the conventional color signal recording circuit is converted into a recording signal in the same manner as in the conventional example. Numeral 1 is input to a head via a recording amplifier and recorded.

As described above, according to the present embodiment, 4.43 MHz N
By adding a carrier color frequency conversion unit 8 from a 3.58 MHz system to a 4.43 MHz system before the TSC and PAL color signal recording circuits, 3.58 MHz NTSC system and M-P as | f2-f1 |
AL8, N-PAL color signal is 3.58M as f2
4.Before color signal recording circuit of HzNTSC system and 3.58MHz PAL system
By adding the carrier color frequency converter 8 from 43 MHz system to 3.58 MHz system, the f1 + f2 can be set to 4.43 MHz NTSC, P
AL color signals can be easily recorded with a smaller circuit size and lower cost than before.

According to the present invention described above, according to the present, the oscillator and carrier chrominance frequency converting circuit composed of a frequency converter and a selection circuit, by adding in front of the color signal recording circuit, the frequency f ₂ Carrier chrominance signal, frequency f ₁ + f ₂ , or frequency | f ₂ −f
₁ | At least one of the carrier color signals
Recording can be easily performed with a smaller circuit size and lower cost than before.

[Brief description of the drawings]

FIG. 1 is a block diagram of a color signal recording circuit of a magnetic recording and reproducing apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams of a color signal recording circuit of a conventional magnetic recording and reproducing apparatus. 1… 3.58MHz BPF, 2,10,14 …… Frequency conversion circuit, 3
…… 3.58MHz NTSC oscillator, 4 …… M-PAL oscillator, 5
... N-PAL oscillator, 6, 7 ... Selection circuit, 8 ... Carrier color frequency converter, 9 ... 4.43 MHz BPF, 11 ... 1.6 MHz LPF, 1
2 ... mixed circuit, 13 ... APC circuit, 15 ... 5.06MHz BPF, 16
…… Rotary circuit, 17… 1/2 frequency divider circuit, 18 …… VCO,
19 ... LPF, 20 ... Phase comparison circuit, 21 ... Division circuit, a
... An input carrier color signal, a '... An output carrier color signal of the carrier color frequency converter, d... A horizontal synchronization signal, k... A modulated luminance signal, l.

Claims (1)

(57) [Claims] 1. A least and one oscillator oscillation frequency is f _1, the frequency f ₁ of the output signal and the input carrier chrominance signal and a multiplying two signals sum or difference frequency carrier chrominance signal of from the oscillator a frequency converter for outputting a carrier chrominance frequency conversion circuit composed of a selection circuit which selects and outputs the output signal of the input carrier chrominance signal or said frequency converter, processes the input carrier chrominance signal of frequency f ₂ magnetic recording at least one carrier chrominance signal of the carrier chrominance signal of | prepended to a chrominance signal recording circuit, the carrier chrominance signal of frequency f _2, the frequency f ₁ + f ₂ or frequencies, for | f ₂ -f ₁ Recording and playback device.