JPS6313587A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To reproduce signals in an appropriate mode with the aid of a pilot signal in a reproducing action and to use the pilot signal as a tracking servo signal by multi-recording the pilot signal when signals are recorded in either mode out of two recording modes. CONSTITUTION:A pilot signal generator circuit 5 and a switch circuit 6 sequentially and circulating frequency-multiplex plural pilot signals with different frequencies with a recording video signal by fields in either one of a standard recording mode and a high quality recording mode. A level detector 24, switches 25 and 26, and FM demodulators 30a and 30b reproduce a tape-like magnetic recording medium, detect whether the pilot signal is present or not, discriminate the standard or high quality mode, and process a reproduction video signal. On the other hand, the pilot signal generator circuit 5, the switch circuit 6, frequency difference detection circuits 391 and 392 and a level difference detection circuit 40 detect the frequency difference between the pilot signals, use said signals as the tracking servo signal, and surely discriminate the modes.

Description

[Detailed Description of the Invention] Industry, Field of Application 1- The present invention relates to a magnetic recording and reproducing device, and in particular, it records by switching between two modes with different carrier frequencies, and automatically switches between these modes for reproduction. The present invention relates to a magnetic recording and reproducing device.

2. Description of the Related Art In recent years, the performance of magnetic tapes and magnetic heads has improved, and there has been a demand for VTRs with higher resolution and higher image quality. For this reason, for example, instead of the standard magnetic tape that uses iron oxide magnetic material used in current home VTRs, high-performance magnetic tape that uses metal, vapor deposition, barium ferrite, etc. is used. Various high-quality modes have been considered in which recording is performed using a carrier wave frequency that is sufficiently higher than the carrier wave frequency of the standard mode used in home VTRs.

Problems to be Solved by the Invention Incidentally, since there is no compatibility between signals recorded in modes with different carrier frequencies, it is possible to convert signals recorded in one mode into the other mode. cannot be played.

For this reason, for example, it is possible to provide a playback mode changeover switch to switch between both modes during playback, and operate this switch after determining in which mode the cassette to be played back was recorded. However, this method not only requires very complicated operations and is extremely inconvenient to use, but also has the problem that it is difficult to determine in which mode the cassette being played back was recorded.

Also, when recording, even high-performance cassettes may be recorded in standard mode, so when playing back such cassettes, each cassette may be played in a different mode, and in some cases, there is a risk that it may be mistaken for a malfunction. There were some problems.

-41 The present invention multiplex-records a pilot signal for mode discrimination and 1 to racking control in the lower band of the low-pass conversion color signal when recording one of the modes, and at the same time, during reproduction, the pilot signal for mode discrimination is 1 - A magnetic device that automatically detects the presence or absence of a signal so that it can be reproduced at an appropriate need, and also detects the frequency difference between pilot signals reproduced from adjacent tracks and uses it as a tracking servo signal for the reproduction head. The purpose is to provide recording and playback equipment.

Means for Solving the Problems In FIG. 1, the FM modulators 4a and 4b use a predetermined carrier frequency to obtain a distributed video signal for the standard recording mode, while using a carrier frequency higher than the predetermined carrier frequency. Means for obtaining a recorded video signal for high image quality mode, pilot signal generation circuit5. The switch circuit 6 is a means for sequentially and cyclically frequency-multiplexing a plurality of pilot signals having different frequencies on a distributed video signal in one of the standard recording mode and high-quality recording mode for each field;
Switch 10. Il air head 151.152 is marked tP-
Means for switching between a recording mode and a high-quality recording mode and recording each signal on a track inclined with respect to the tape running direction of a tape-shaped magnetic recording medium, a level detector 24, a switch 25, 26 . The 1M demodulators 30a and 30b reproduce the tape-shaped magnetic recording medium, detect the presence or absence of the pilot signal, determine the standard mode or the high-quality mode, switch the corresponding mode, and process the reproduced video signal. The signal generation circuit 5, the switch circuit 6, the frequency difference detection circuits 39+, 392, and the level difference detection circuit 40 detect the frequency difference between pilot signals reproduced from mutually adjacent tracks on the tape-shaped magnetic recording medium. 3A and 3B are examples of means for obtaining a tracking servo signal and controlling tracking using the I-racking servo signal.

During action playback, the presence or absence of a pilot signal is detected and the mode is switched for signal processing, while the frequency difference between the pilot signals is detected and used as a tracking servo signal to ensure mode discrimination and improve usability. .

Embodiment FIG. 1A shows a block system diagram of an embodiment of the recording system of the apparatus of the present invention. In the figure, the video signal input to the terminal 1 is filtered through a low-pass filter and comb filter 2a with a cutoff frequency of, for example, about 3Ml-IZ, and a low-pass filter and comb filter with a cutoff frequency of, for example, about 5MH2. 2b, where it is made into a luminance signal component, high-frequency amplified by pre-emphasis circuits 3a, 3b, respectively, and supplied to FM modulators 4a, 4b. FM converter 4
In a, the carrier frequency is 5.01yl Hz ~ as described later.
FM modulation is performed using 6 and 7 MHz to produce a high-quality mode FMllii signal, while the FM modulator 4b
Then, the carrier frequency is 3.4MHz ~ 4.4pJj @
FM modulation is performed using z to produce a standard mode FMN degree signal.

In the standard mode, the frequency spectrum of the FM luminance signal is as shown by ■ in FIG. 2, and in the high-quality mode, the carrier frequency is set higher than in the standard mode, as shown by ■ in the same figure.

In the frequency spectrum of the FM luminance signal shown in Figure 2,
fAS, fAP, and fAW represent the carrier wave frequencies at the sync tip level S, pedestal level P, and white peak level W of the luminance signal shown in FIG. fsw
is the sync chip level S of the luminance signal. The carrier frequency at the pedestal level P and the white peak level W is shown. For example, the carrier frequency fAS in standard mode is 3
．． 4MHz, fA P is 3.8MHz, fA
w is 4.4M1lZ, the above carrier frequency fes in high image quality mode is 5.0MHz, and fap is 5.6
MHz.

few is 6.7M HZ.

On the other hand, mode discrimination and tracking servo pilot signals f+, fz, fa, and f4 having different frequencies from the pilot signal generation circuit 5 are supplied to a switch circuit 6, where they are sent to a drum with a two-field period from a terminal 7. The switching pulses sequentially switch cyclically for each field (that is, f+, fz for each odd field and even field.

fa, f4. 'f+, f2. f3. ...) was taken out,
The filter 8 adds the signal to the high-quality mode luminance signal from the FM modulator 4a. The high image quality mode brightness signal from the filter 8 and the standard mode brightness signal from the FM modulator 4b are switched to a switch 10 according to the mode selected by the recorded poetry mode changeover switch 9.
The signal is supplied to the swindler 11 via.

On the other hand, the video signal input to the terminal 1 is converted into a chroma signal by a bandpass filter 12, subjected to signal processing by a recording chroma processing circuit 13, and then added to an FM luminance signal by a adder 11. The output of the adder 111 is amplified by the recording amplifier 14, supplied to magnetic heads 151 and 152, and recorded on the magnetic tape 16.

In this case, as shown in FIG. 4(A), the high-quality mode recording signal has a pilot signal f+ in the lower band of the chroma signal C.
, fz, f3. f4 is superimposed, whereas the standard mode recording signal does not have the upper two pilot signals, as shown in FIG. 13 (13).

Next, the operation during playback will be explained. FIG. 1(B) shows a block system diagram of an embodiment of the reproduction system of the apparatus of the present invention.

In the figure, a frequency division multiplexed signal of an FM luminance signal and a low frequency conversion carrier chrominance signal recorded in a magnetic chip 116 is alternately reproduced by magnetic heads 151 and 152, and is output from a terminal 7 through preamplifiers 171 and 172. The signal is supplied to a switch 18 that is switched by a drum switching pulse, where it is converted into a continuous signal and then supplied to a high-pass filter 19, a low-pass filter 20, and a bandpass filter 21.゛The signal near the pilot signal frequency divided by the bandpass filter 21 is supplied to the envelope detection circuit 23 and the level detection circuit 24 via the buffer 7 amplifier 22.
Here, in high image quality mode, pilot signals f1 to f
4, this is detected and switch 25.26.27
is switched to terminal A (high image quality mode), and if no pilot signal is detected, switches 25, 26, and 27 are switched to terminal B (standard mode). The reproduced FM luminance signal separated into P waves by the ^-band filter 19 is sent to the equalizer circuit 28 in high image quality mode via the switched switch 25.
a and the equalizer circuit 28b in the standard mode to the limiter 29, where amplitude fluctuation components are removed, and the high-quality mode re-1 system FM demodulator 30a, low-pass filter 31a1 de-emphasis circuit 32a1 switched switch 26 is supplied to the adder 33 via the FMI modulator 30b and low-pass filter 31 of the standard mode reproduction system.
The b1 de-emphasis circuit 32b1 is supplied to the adder 33 via the switch 26 changed over.

Further, the reproduced signal taken out from the switch 18 described above is filtered by a low-pass filter 20 into a low-pass converted carrier color signal.
After being subjected to f-filtering, jitter is removed by the reproduction chroma processing circuit 34 using known means and the signal is returned to the reproduction carrier color signal of the original band. The adder circuit 33 combines this reproduced carrier color signal with the reproduced luminance signal taken out from the switch 26 and reproduced and demodulated by the reproduction system in the same mode as that at the time of recording, and sends the resultant signal to an output terminal 35 as a reproduced color video signal. Output.

Here, in the standard mode, the switch 27 is connected to terminal B, so the control signal reproduced by the control head 36 from the magnetic tape 16 is converted into a tracking servo signal by the tracking servo circuit 37.
A magnetic tape running circuit (not shown) is connected via switch 27.
The running speed of the magnetic head 116 is controlled so that the magnetic head traces 151° 152 without any tracking deviation.

On the other hand, in the high image quality mode, the switch 27 is connected to the terminal, so it is controlled by a tracking servo signal obtained by the tracking servo method described below. This tracking servo system is disclosed, for example, in Japanese Patent Laid-Open No. 60-59559 (title of the invention: "Tracking Control Device").

Reference pilot signals fl, f2 . f3. f4 is multiplied by the reproduced pilot signal from the bandpass filter 21 in the multiplier 38, and if there is a tracking deviation in the magnetic head 151 or 152, the difference between the frequency component of the reproduced pilot signal and the frequency component of the reference pilot signal is A signal having a frequency of is extracted and supplied to frequency difference detection circuits 39+ and 392 composed of bandpass filters and the like.

In this case, the pilot signals f1 to f4 are, for example, lf
+ -f21=lfs -f41=fA, l f2 f
3 l=l f4-f+ 1=fe, so the magnetic heads 151 and 152 are odd (even)
If the track shifts to the right (left) during playback, the frequency difference detection circuit 391 extracts a detection signal having a frequency difference fA and a level corresponding to the amount of tracking shift. If it shifts to the right), the frequency difference detection circuit 392
A detection signal having a frequency difference f8 and a level corresponding to the tracking deviation is extracted. Note that if the magnetic heads 151 and 152 are accurately tracing the track without tracking deviation, the frequency difference detection circuit 39
+, the output signal level of 392 is zero.

The output signals of the frequency difference detection circuits 39+ and 392 are supplied to a level difference detection circuit 40 to detect a level difference, and are used as, for example, a positive level signal in a rightward shift state and a negative level signal in a leftward shift state. The output signal of the level difference detection circuit 40 is bolded in the hold circuit 41 at the timing of the drum switching pulse from the terminal 7, unnecessary frequency components are removed by the low-pass filter 42, and taken out as a tracking servo signal via the switch 27. .

Note that the present invention does not take into consideration reverse H conversion, in which a magnetic tape recorded in high-quality mode using the apparatus of the present invention is reproduced using conventional equipment (standard mode only). Therefore, since general control signals are not recorded on the control track of the magnetic tape during high-quality mode recording, other information such as an address can be recorded on this control track.

Further, the mode in which the pilot signal is superimposed is not limited to the high image quality mode, but may be superimposed in the standard mode.

Effects of the Invention According to the device of the present invention, during playback, the presence or absence of a pilot signal is detected and the mode is automatically switched, so there is no need to judge in which mode the cassette was recorded or to perform a complicated mode switching operation. It is easy to use, and also,
Since the pilot signal is frequency-multiplexed onto the video signal as a tracking servo signal, it has the advantage of being able to record other information on the control track of a general magnetic tape.

[Brief explanation of drawings]

FIG. 1 is a block system diagram of one embodiment of the device of the present invention, and FIG.
The figure shows the frequency spectrum of the FM brightness signal, FIG. 3 shows the waveform of the brightness signal, and FIG. 4 shows the frequency spectrum of the composite video signal. DESCRIPTION OF SYMBOLS 1... Video signal input terminal, 4a, 4b... FM modulator, 5... Pilot signal generation circuit, 6... Switch = 15 - circuit, 7... Drum switching pulse input terminal, 8... ... Adder, 9... Recording mode changeover switch, 10.25
゜26.27...Switch, 151.152...Magnetic head, 16...Magnetic tape, 19...High-pass filter, 21...Band filter, 23...Envelope detection circuit, 24... ...Level detection circuit, 30a, 30
b... FM demodulator, 38... Multiplier, 39+, 3
92...Frequency difference detection circuit, 40...Level difference detection circuit.

Claims (6)

[Claims] (1) means for obtaining a recorded video signal for a standard recording mode using a predetermined carrier wave frequency, and a means for obtaining a recorded video signal for a high image quality mode using a carrier wave frequency higher than the predetermined carrier frequency; Means for frequency multiplexing a pilot signal on the recorded video signal of one of the high-definition recording modes, and means for switching between the standard recording mode and the high-definition recording mode and transmitting each signal to the tape of the tape-shaped magnetic recording medium. 1. A magnetic recording device comprising means for recording on a track inclined with respect to a running direction. (2) The recorded video signal is a signal obtained by frequency multiplexing a luminance signal FM modulated by the carrier wave frequency and a low-frequency converted color signal, and the pilot signal is a signal in the lower band of the low-frequency converted color signal. 2. The magnetic recording device according to claim 1, wherein the signal is frequency-multiplexed. (3) The magnetic recording device according to claim 1 or 2, wherein the pilot signal is a plurality of signals each having a different frequency, and is recorded sequentially and cyclically for each field. . (4) Means for obtaining a recorded video signal for a standard recording mode using a predetermined carrier frequency, and a means for obtaining a recorded video signal for a high image quality mode using a carrier frequency higher than the predetermined carrier frequency; Means for frequency multiplexing a pilot signal on the recorded video signal of one of the high-definition recording modes, and means for switching between the standard recording mode and the high-definition recording mode and transmitting each signal to the tape of the tape-shaped magnetic recording medium. A means for recording on a track inclined with respect to the running direction, a means for reproducing the tape-shaped magnetic recording medium, detecting the presence or absence of the pilot signal, determining the standard mode or the high-quality mode, and switching to the corresponding mode. 1. A magnetic recording and reproducing device comprising means for signal processing a reproduced video signal. (5) The magnetic recording and reproducing apparatus according to claim 4, wherein the pilot signals are a plurality of signals having different frequencies, and are sequentially and cyclically recorded for each field. (6) means for obtaining a recorded video signal for a standard recording mode using a predetermined carrier frequency, and a means for obtaining a recorded video signal for a high image quality mode using a carrier frequency higher than the predetermined carrier frequency; Means for sequentially and cyclically frequency multiplexing a plurality of pilot signals having different frequencies on the recorded video signal of one of the high-quality recording modes for each field; means for recording each signal on a track inclined with respect to the tape running direction of the tape-shaped magnetic recording medium by switching the recording medium; Alternatively, a means for determining a high image quality mode, switching to a corresponding mode, and signal processing a reproduced video signal, and detecting a frequency difference between pilot signals reproduced from mutually adjacent tracks on the tape-shaped magnetic recording medium to generate a tracking servo signal. What is claimed is: 1. A magnetic recording and reproducing apparatus comprising means for obtaining a tracking servo signal and performing tracking control using the tracking servo signal.