JPH0482052A - Vtr - Google Patents

Abstract

PURPOSE:To prevent a user from feeling incompatibility or being irritated by taking out an audio signal demodulated from an FM audio signal in the period when the equalizer characteristic is set and taking out an audio signal demodulated from a PCM audio signal after this period. CONSTITUTION:Audio signals L and R demodulated from FM audio signals SM and SS are taken out from a switch circuit 25 in the period when the equalizer characteristic of a reproducing equalizer circuit 32 is set. After this period, audio signals L and R demodulated from a PCM audio signal SA are taken out from the switch circuit 25. Consequently, audio signals L and R demodulated from FM signals SM and SS are outputted during setting of this characteristic through it takes one second or longer to set the equalizer characteristic of the reproducing equalizer circuit 32. Thus, the user is prevented from feeling incompatibility or being irritated.

Description

[Detailed description of the invention] The explanation will be given in the following order.

A. Field of industrial application B. Overview of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem (Fig. 1) F. Effect G. Example G, First example (first example) Figures to Figures 4) G2 Second embodiment (Figures 5 to 8) G, Third embodiment (Figure 9) G4 Other embodiments H Effects of the invention A Industrial application field This The invention relates to a VTR.

B. Summary of the Invention This invention provides, for example, when playing an 8mm video,
At the start of playback, the audio signal is played back from the FM audio signal, and then, when the playback mode of the PCM audio signal becomes stable, the audio signal is played back from the PCM audio signal, thereby ensuring that the audio signal can be played back. It is.

C. Prior Art In 8 mm video, the video signal is recorded as shown in FIGS. 10 and 11.

That is, as shown in FIG. 10, the sum signal (L+R) of the FM signal SF modulated by the luminance signal SY, the carrier color signal SC subjected to low frequency conversion, and the left and right channel audio signals R is FM signal S color modulated by
FM signal SS modulated by the difference signal (L-R) and pilot signal SP for tracking servo during playback
are frequency multiplexed.

Then, the multiplexed signal Sv is transferred to the magnetic tape (2v) as one diagonal video track (2v) for each field period, as shown in FIG.
) is recorded.

In this case, the frequency of the FM brightness signal SF is the brightness signal SY
The sync chip level is 4.2 MHz, and the white peak is 5.4 MHz (hereinafter, this is referred to as the "standard mode". The numerical values are for the NTSC system. The same applies hereinafter).

Furthermore, when an audio signal is converted into a PCM signal and recorded, it is recorded according to the standards shown in the second column of FIG. 12. In other words, the audio signal has a horizontal frequency fh twice ('
At a sampling frequency of 31.5kHz), the sample is quantized into a 10-bit digital signal, and each sample is 10 bits to 8 bits.

This pi-phase mark signal is compressed non-linearly into a high-phase mark signal, and this high-phase mark signal is applied to an overscan section on the front side of the video track (2v) at an angle of 36°, as shown in FIG. The range is recorded as a PCM audio track (2A) (hereinafter referred to as '
(referred to as "NRML mode").

However, in 8 mm video, the image quality has been improved compared to the above-mentioned standard mode specifications. That is, when improving image quality, the frequency of the FM luminance signal SF is set to 5.7 Hz at the sync chip level of the luminance signal SY and 7.7 MHz at the white beak (hereinafter, this is referred to as "bi-band mode"). ).

Along with this increase in image quality, improvements in the sound quality of PCM audio are also being considered, but in the case of this improvement in sound quality, there are linear mode and non-linear mode (hereinafter referred to as "L mode J" and "L mode J" and "nonlinear mode", respectively). ``N mode j'').

That is, in the L mode, as shown in the third column of FIG. 12, the sampling frequency is 48kHz,
One sample is quantized into a 16-bit digital signal by either 44.1kl(z or 32kl(z), the digital signal is 8-10 converted, and the converted signal is
In the overscan section on the front side of the video trunk (2v), an angular range of 41° is recorded as a trunk (2A).

Furthermore, in the N mode, one sample of the quantized digital signal is 16
Bit 7) is non-linearly compressed to 12 bits and recorded in the same way as in the mustard mode.

Therefore, according to this new PCM audio standard, audio signals can be recorded and reproduced with characteristics equal to or better than those of CDs and R-DATs.

As mentioned above, for 8mm video, standards for standard mode and NRML mode were first established, then as technology improved, standards for high band mode were added, and then L mode and N mode. Standards have been added.

Since 8mm video has progressed as described above, tape cassettes exclusively for standard mode and NRML mode were first prepared.

This tape cassette uses a standard type coated tape (hereinafter, this cassette will be referred to as 'MP tape').

However, as a matter of course, this MP tape cannot support high band mode.

Therefore, tape cassettes that can support bi-band mode are available.

Tape cassettes that can support this bi-band mode include those that use high-braid metal coated tape and those that use metal vaporized tape (hereinafter, cassettes that use coated tape are referred to as r
HGMP tape", and cassettes using vapor-deposited tape are called "rME tape").

These HGMP tapes and ME tapes can be used not only in high band mode (but also in L mode and N mode).

D Problems to be Solved by the Invention Incidentally, MP tape, HGMP tape, and ME tape naturally have different magnetic properties from each other, as shown in FIG. 13.

Also, as shown in Figure 12, the PCM mote allows
The transmission rate of PCM audio signals differs greatly.

Therefore, during playback, it is necessary to set the playback equalizer characteristics of the PCM audio signal system in accordance with the tape type and PCM mode.

However, this playback equalizer characteristic setting is
M reproduce the audio signal.

■ Determine the PCM mode from the reproduced PCM audio signal.

■ Set the playback equalizer characteristics according to the determination result.

Since the steps are performed in this order, it takes about one second from when the setting is instructed until the demodulation of the PCM audio signal is actually performed.

Therefore, even if you press the playback key for an 8mm video, the audio will not be output until about 1 second has passed.
This may make the user feel uncomfortable or irritated.

This invention attempts to solve these problems.

E. Means for Solving the Problems Now, considering the 8mm video standard, recording or playing back audio signals in PCM format is an option. However, FM recording and playback of audio signals is
It is considered mandatory.

This invention focuses on such points.

That is, in this invention, in correspondence with the embodiments described later, the FMR intensity signal SF modulated by the luminance signal sy, and the FM audio signals SM and SS modulated by the audio signal R,
and the audio signal R, the PCM audio audio signal S modulated by R, the audio signal from the recorded magnetic tape (2),
In a VTR that reproduces R and luminance signals sy, rotating magnetic heads (18) and (IB) generate FM luminance signals SF, FM audio signals SM, SS and PCM audio audio signals S from a magnetic tape (2); a reproduction equalizer circuit (32) that performs predetermined reproduction equalization processing on the reproduced PCM audio audio signal S;
FM demodulation circuits (23M) and (23S) that demodulate R;
A circuit (37) that demodulates the PCM audio audio signal S vs. audio signal R and R from the reproduction equalizer circuit (32) -7 (3
9) and the audio signal demodulated from the FM audio signals SM and SS, and the R
and the audio signal demodulated from the PCM audio signal S^, R
A switch circuit (25) for selectively taking out the information is provided.

During the period in which the equalizer characteristics of the F action reproduction equalizer circuit (32) are being set, the audio signal R demodulated from the FM audio signals SM and SS is taken out from the switch circuit (25), and the reproduction equalizer circuit ( When the setting of the equalizer characteristics (32) is completed, the PCM audio signal S demodulated audio signal R is taken out from the switch circuit (25).

G Example G1 First Example In FIG.
(not shown) at the frame frequency. The magnetic tape (2) is run obliquely at a constant speed over an angular range of just over 221 degrees with respect to the rotating peripheral surfaces of the heads (IA) and (1B).

Incidentally, trunks (2A) and (2v) are formed on the tape (2) as explained in FIG. 11. Furthermore, in the following description, the signal of track (2A) will be collectively referred to as a PCM audio signal S^.

Furthermore, (3) indicates a system controller, and the second system controller (3) is composed of a microcomputer,
Control signals are supplied from this system controller (3) to circuits to be described later to control the operation of the entire VTR.

In addition, (4) indicates a tape sensor, and this sensor (4)
The TD hole of a tape cassette (not shown) detects whether the cassette is an MP tape, HGMP tape, or ME tape, and the detection output is supplied to the system controller (3). Furthermore, (6) shows a timing signal forming circuit, and in this forming circuit (6), various clocks and timing signals synchronized with the video signal are formed and supplied to the respective circuits.

Further, (7) indicates an operation key, and the output of this operation key (7) is supplied to the system controller (3).

Then, tape (2
) are alternately reproduced every field period, and these signals SV and SA are sent to the switch circuit (12) via the head amplifiers (IIA) and (IIB).
), the switch circuit (12) is alternately switched every field period, and the signal Sv of each field period is continuously taken out from the switch circuit (12).

This signal Sv is then supplied to the video reproduction processing circuit (14) through the reproduction amplifier (13), the original color composite video signal is taken out from the signals SF and SC in the signal SV, and this signal is sent to the terminal ( 15).

Further, the signal Sv from the amplifier (13) is supplied to the bandpass filter (21M) to extract the FM signal Sl'l, and this signal needle is supplied to the FM demodulation circuit (23M) through the limiter (22M) and summed. The signal (L+R) is demodulated, and this signal (L+R) is sent to the matrix circuit (24).
supplied to

Further, the signal Sv from the amplifier (13) is supplied to a bandpass filter (215) to extract the FM signal S, and this signal SS is supplied to the FM demodulation circuit (23S) through a limiter (22S) to generate a difference signal. (L-R) is demodulated, and this signal (L-R) is sent to the matrix circuit (24).
supplied to

Then, in the matrix circuit (24), the original audio signal R, R is matrixed from the signals (R) and (L-R) supplied thereto, and this signal R, R is transferred to the switch circuit (24), which will be described later. 25) through the terminal (26L), (2
6R).

Furthermore, the signals SV and SA from the head amplifiers (11, A) and (IIB) are supplied to the switch circuit (31), and the switch circuit (31) is alternately switched every one field period to switch the switch circuit (31). The number of PCM audio signals S for each field period is output from the circuit (31).

Then, this signal SA is sent to the reproduction equalizer circuit (32)
is supplied to a level comparator circuit (33) for waveform shaping, and is also supplied to a DC level detection circuit (34) to detect the DC level of the signal line, and this detection output is supplied to the comparator circuit (33). Ru. Therefore, the comparison circuit (
33) outputs a signal SA whose waveform is shaped (level regulated) to a "0°" or "°1" level.

Then, this waveform-shaped signal SA is supplied to the data input of the D flip-flop (35), and the signal SA from the comparison circuit (33) is supplied to the clock extraction circuit (36) composed of a PLL or the like. supplied signal SA
A clock CK is extracted from the clock CK, and this clock CK is supplied to the clock input of the flip-flop (35).

Therefore, the signal SA synchronized with the clock CK is taken out from the Frisobfromp (35).

Then, this extracted signal SA is transmitted to the demodulation circuit (37
), the signal is subjected to 10-8 conversion, contrary to the recording process, and then supplied to the reproduction processing circuit (38), where processing such as error correction and time axis expansion is performed, and the original digital audio signal is extracted. This digital audio signal is then supplied to the D/A converter (39) and converted into the original left and right channel audio signals (R, R), and this signal (R, R) is passed through the switch circuit (25) to the terminal (26L). ), (26R).

In this case, the P played from track (2A)
CM audio The CM mode on the audio signal S is NRML mode,
The determining circuit (40) determines which mode is the L mode or the N mode as follows.

That is, the PCM audio signal record from the switch circuit (31) is supplied to the equalizer amplifier (41). This equalizer amplifier (41) is an equalization circuit designed to obtain a certain degree of eye aperture ratio for the reproduced PCM audio signal S, regardless of the CM mode of the signal SA. Therefore, when the signal SA passes through this equalizer amplifier (41), code amount interference is removed to some extent.

Then, the signal SA from this equalizer amplifier (41)
However, the band pass filters (42L), (42N), (4
2R), and its filter output is supplied to the detection circuit (43
L), (43N), and (43R), respectively.

In this case, the filter (42L) has an L mode PCM audio signal record as its passband, and therefore
If the CM audio signal S is recorded in the upper mode, the detection circuit (43L) outputs a signal SL indicating the level of the L mode signal SA.

Furthermore, the filter (42N) filters the upper band of the N-mode PCM audio signal S, and therefore
If the M audio audio signal S is recorded in the upper mode, the detection circuit (43N) outputs a signal SN indicating the level of the N mode signal SA.

Furthermore, the filter (42R) is connected to the PC in NRML mode.
Therefore, if the PCM audio signal S is recorded in the RML mode, the detection circuit (43R) outputs a signal SR indicating the level of the signal recorded in the NR mode. is output.

These signals SL, SN, and SR are then supplied to the system controller (3) through waveform shaping circuits (44L), (44N), and (44R).

And in the system controller (3), the shaping circuit (44L)
Based on the signals 5L-5R from ~(44R), it is determined whether the CM mode on the reproduced PCM audio audio signal S is NRML mode, L mode, or N mode, and the output signal of the determination is The reproduction equalizer characteristics of the reproduction equalizer circuit (32) and the clock extraction circuit (3) are determined by the MD.
The extraction characteristics of 6), the demodulation characteristics of the demodulation circuit (37), the processing characteristics such as error correction characteristics of the processing circuit (38), and the conversion characteristics of the converter (39) are switched to characteristics corresponding to the PCM mode at the time of recording. .

Regarding the reproduction equalizer circuit (32), the reproduction equalizer characteristics are switched depending on the type of tape (2) based on the output of the sensor (4) in accordance with the characteristics shown in FIG. 13.

Furthermore, in order to output the sound immediately when the playback key is pressed, the above-mentioned switch circuit (25) is provided, and the error rate is output from the syndrome generator (not shown) of the processing circuit (38). Signal XERR
is taken out, and this signal XERR is supplied to the system controller (3).

Further, in the system controller (3), for example, a routine (100) shown in FIG. 2 is executed.

That is, when the play key of the keys (7) is pressed, the routine (100) starts from step (101),
In step (102), the VTR is put into playback mode and playback of the signals SA and SV is started.Subsequently, in step (103), the system controller (3) switches the switch circuit (25) to the matrix circuit (24) as shown in the figure. can be switched to the side.

In this case, when the VTR enters playback mode, the multiplexed signal S
Since v can be obtained immediately, from the time of step (103), the audio signal R is demodulated from the FM signals SM and SS included in the signal SV, and this signal R is demodulated by the switch circuit (
25) and are taken out to terminals (26L) and (26R).

In this way, when the playback key is pressed, the VTR starts playing, and first, the audio signals R and R from the FM signals SM and SS are output.

Subsequently, in step (104), the signal 5L-SR
By checking the presence or absence of the PCM audio signal S
If no pair is checked and none of the signals SL to SR are obtained, that is, when no PCM audio signal S is generated, the process starts from step (104) to step (1).
Return to 03).

Therefore, while the PCM audio signal S is not generated,
Steps (103) and (104,) are repeated, and FM
The audio signal R is reproduced from the signal needle SS, and the presence or absence of the PCM signal SA continues to be checked.

Therefore, when the PCM audio signal S is recorded from the middle of the tape (2), this step (103
), (104), the PCM sound south signal S^ is detected.

Then, when any of the signals 5L-3R is obtained, that is, when the PCM signal SA is obtained, this step (
104), and the process proceeds to step (104).
The process then proceeds to step (111).

Therefore, when the PCM audio signal S is matched from the start of playback (at this time, the playback equalizer does not have sufficient characteristics yet), steps (103) and (104)
), the process immediately proceeds from step (104) to step (111).

Then, in this step (111), it is checked whether the obtained signal is the signal SR, and the signal SR
When , the process moves from step (111) to step (
113), and in this step (113), the circuits (32), (36) to (39) are NRM
Controlled by L mode playback characteristics.

Further, in step (111), when the obtained signal is not the signal SR, the process proceeds from step (111) to step (112), and this step (112)
At step (1), it is checked whether the obtained signal is the signal SL, and if it is the signal SL, the process proceeds to step (1).
12) to step (114), and this step (
114), the signal MD causes the circuits (32) and (3
6) to (39) are controlled to the L mode reproduction characteristics. Furthermore, in step (112), when the obtained signal is not the signal SL, the process proceeds from step (112) to step (115);
, circuits (32), (36) to (3) are connected between the signals.
9) is controlled to have N mode reproduction characteristics.

Then, in steps (113) to (115), P
When the CM audio audio signal S characteristics are respectively controlled,
The process proceeds to step (121), and this step (12
In 1), the equalizer characteristics of the reproduction equalizer circuit (32) are controlled so that the error rate indicated by the signal XERR is minimized. Note that, as a control method at this time, for example, a hill climbing method can be used.

Then, in step (121), when the reproduction equalizer characteristics are controlled so that the error rate indicated by the signal XERR is minimized, the process proceeds from step (121) to step (122), and in this step , it is checked whether the error rate is less than or equal to a predetermined value, and if the error rate is less than or equal to the predetermined value, the process proceeds from step (122) to step (123);
In this step (123), the FM signals SM, SS
It is checked whether R is being played, and if it is, the process proceeds to step (1).
23) to step (124), and this step (
124), the switch circuit (25) is switched to the converter (39) side by the system controller (3).

Therefore, from this switching point on, the PCM audio audio signal S versus the demodulated audio signal R, R is
5) and are taken out to terminals (26L) and (26R).

That is, when you press the playback key, the FM signals SM, S
The audio signals R and R are played back from S, and during this time the playback equalizer characteristics for the PCM audio audio signal S are set, and when the settings are completed, the audio signals R and R of the PCM audio signal S pair are played back. It will be switched to.

Then, in step (124), the switch circuit (
25), the process proceeds to step (12).
Returning to step 2), the error rate is checked again. Further, in step (123), even when the audio signals R and R are not reproduced from the FM signals SM and SS, the process returns from step (123) to step (122).

In this way, steps (122) to (124) are repeated as long as the error rate is less than or equal to the predetermined value 1, and the reproduction of the audio signals R and PCM audio signal pair S continues, and the error rate is checked. There is.

Further, in step (122), when the error rate exceeds a predetermined value, for example, if the PC
If the M audio audio signal S pair has not been recorded, the process returns from step (122) to step (103).

Thus, according to the present invention, when the playback key is pressed, the audio signals R and R are first played from the FM signals SM and SS, and during this time, the playback equalizer characteristics for the PCM audio signal S are set. Once the settings are complete,
The PCM audio signal S pair of audio signals is switched to playback of the R audio signal.

Therefore, even if it takes more than one second to set the equalizer characteristics of the playback equalizer circuit (32) after the playback key is pressed, during the setting, the FM signal needle, the audio signal from the SS, and the R Since the information is output, the user does not feel uncomfortable or irritated.

Then, an equalizer circuit (
Immediately after setting the equalizer characteristics in 32),
Since the audio signal of the CM audio audio signal pair S is switched to the R audio signal, a high quality audio signal can be reproduced.

In addition, when the PCM audio signal S pair is not recorded, the FM signal needle, the audio signal R from the SS, and the R are automatically output, so the user needs to be aware of the presence or absence of the PCM audio signal S pair recording. There is no.

FIG. 3 shows an example of a reproduction equalizer circuit (32).

That is, the PCM audio audio signal S from the switch circuit (31) is passed through the equalizer amplifier (321), and further passed through the delay circuit (322) to the level comparison circuit (32).
3), and the signal SA from the amplifier (321) is also supplied to the comparison circuit (323) through the variable attenuator circuit (324).

In this case, the equalizer amplifier (321) has equalizer characteristics similar to those of the equalizer amplifier (41).

Also, from the system controller (3) to the attenuator circuit (324)
The control signal is supplied to

Therefore, now: ■ o: Output voltage of equalizer amplifier (321) (= signal SA) ■ I: Output voltage of delay circuit (322) ■ z: Output voltage of antenna circuit (324) ■ 4: Comparator circuit (323) When the output voltage of
τ)) τ: delay time of delay circuit (322): coefficient of attenuator circuit (324), then V4=V, -V2 = Asinω(t-τ) k (Asinωt + As1r+ω(t 2 r)
)=A sinω(t −r) (1−2k cosωr
).

Therefore, the number of transmission gaps G at this time is G=■4/■.

CC1-2kcosωr, and if the coefficient k is controlled, the equalizer characteristics change as shown in Figure 4, so this coefficient k is
), desired equalizer characteristics can be obtained. Note that this coefficient can be determined by the hill-climbing method as described above.

G2 Second Embodiment Generally speaking, in a magnetic recording and reproducing device, the reproduction output of the head increases in proportion to the signal frequency, but once a certain frequency is exceeded, the reproduction output decreases as the frequency increases due to various losses. starts to decline.

In the case of a VTR, the frequency at which the reproduced output decreases is in the band of the FM luminance signal, and a decrease in the level of the FM luminance signal leads to deterioration in image quality.

Therefore, in general VTRs, during reproduction, peaking is applied to the reproduced FM luminance signal to prevent the level of the FM luminance signal from decreasing and to prevent deterioration of image quality. For example, in the case of 8 mm video, as shown by the solid line in FIG. 6A, peaking is applied so that the peak is around 7 MHz to prevent the level of the FM luminance signal SF from decreasing.

However, in the case of 8mm video, applying peaking can prevent the level of the FM luminance signal SF from decreasing, but as shown by the broken line in Figure 6A, the group delay characteristic changes in the peaking band and its vicinity. This results in distortion.

If the PCM audio signal SA is in the NRML mode, the shortest recording wavelength is relatively long, so even if there is some group delay distortion, the influence of the distortion can be compensated for in the reproduction equalizer circuit (32). However, when the shortest recording wavelength becomes short, such as in I mode or N mode, the reproduction equalizer circuit (32) cannot sufficiently compensate for the effects of distortion, so the PCM audio signal S
A's error rate has worsened.

In this example, such problems are taken into consideration.

Now, the trunk (2A) is shown in detail as shown in FIG. 7. However, in figure A, the PCM audio signal SA is NRML.
In the case of the mode, B in the figure shows the case where the PCM audio signal SA is in the L mode and the N mode (some numerical values are approximate values).

In the case of the NRML mode (A in the same figure), the rear 2.
The section with an angle range of 06° is the Kronklanin section CKRI
Here, the clock frequency is 5.79MHz ('
= 368 f h ) clock run-in signal CKRI
is recorded.

Then, following this interval CKRI, an interval PCMA having an angular range of <26.32° is defined as a data interval PCMA, and here,
Original PCM audio data PCMA is recorded.

Furthermore, following this section PCM^, a section with an angular range of < 2.06° is the post-recording margin section AF[? C, the post-recording margin signal AFRC of the clock frequency is recorded here, and following this section AFRC, a section with an angular range of <2.57° is a guard section VPGD with the video track (2v).
It is said that

Then, this guard section VPGDT:P CM audio track (2A) ends, and the video track (2v) continues thereafter.

In addition, in the case of L mode and N mode (B in the same figure), a section within an angular range of 3 degrees from the beginning of the track (2A) is defined as a margin section MRGN, where 172
(The clock frequency is 1056fh in L mode and 840fh in N mode). Further, a section with an angular range of 2° following this section MI'lGN is set as a preamble section PREM, and a preamble signal P of a predetermined bit pattern is applied to this section.
l? EM is recorded.

And this section PI? Following EM, the section PCMA having an angular range of <31.43 degrees is set as the data section PCMA, and the original PCM audio data PCMA is recorded here.

Furthermore, a section with an angular range of 2 degrees following this section PCMA is defined as a postamble section PSTM, which has a frequency of 172 of the clock frequency, that is, 8.8 in the L mode.
In the 3 MHz, N mode, a 6.6 MHz postamble signal PSTM is recorded, and a section in an angular range of 2.57° following this section PSTM4 is set as a guard section VPGD with the video track (2v).

The PCM audio track (2A) ends at this guard section VPGD, and the video track (2v) continues thereafter.

Therefore, in this example, the heads (IA), (IB)
When scanning at least the PCM voice data section PCMA of the trunk (2A), peaking for the FM degree signal SF is prohibited.

That is, in FIG. 5, the reproduced signals SA, Sν of the head (IA) are supplied to the switch circuits (52A), (12) through the first head amplifier (IIA), and are also supplied to the second head amplifier (53A). ) is supplied to the switch circuit (52A).

In this case, the amplifier (IIA) has a peaking circuit (5
1A) is connected, and the frequency characteristics of the amplifier (IIA) are as follows:
As shown by the solid line in the 6th [DA, the characteristic has a peak around 7 MHz (for this reason, the amplifier (114)
(The group delay characteristic of the amplifier (53A) is the characteristic shown by the broken line in A of the same figure) Furthermore, the frequency characteristic of the amplifier (53A) is a flat characteristic as shown in B of the same figure, and its group delay characteristic is
As shown in Figure C, the PCM audio signal has almost flat characteristics in the S band.

Furthermore, from the timing signal forming circuit (6), FIG.
The outside of the control signal as shown in C is taken out.

That is, Figure A shows the L mode (and N mode) track (2A) and the NR mode trunk (2A) side by side with respect to the position of the video track V). , in the case of PCM audio audio signal S band mode or N mode, the head (IA) (or (IB)) is connected to the track (2A) as shown in A and B of the same figure.
) during the scanning period of the preamble section PREM and the PCM audio data section PCMA, a signal having a "1" level is extracted. In addition, in the case of the PCM audio signal S-band RML mode, as shown in A and C of the same figure, the head (IA) (or (IB)) is connected to the track (
During the period in which the clock run-in interval CKRI and the PCM audio data interval PCMA of 2A) are being scanned, a signal outside of the "1" level is extracted.

Then, this signal outside is supplied to the switch circuit (52A) as its control signal, and when S-=゛0'', the signal from the amplifier (IIA) is supplied to the switch circuit (52A).
is supplied to the switch circuit (31) through S−=“′
1'', the signal from the amplifier (53A) is supplied to the switch circuit (31) through the switch circuit (52A).

The head (IB) is also configured in the same way as the head (IA), and the circuit (IIA), (51
The circuits corresponding to A) to (53A) have the suffix A.
The suffix B will be added instead, and the explanation will be omitted.

According to such a configuration, when the multiplexed signal SV is reproduced by the head (IA), this signal SV is transmitted from the amplifier (IIA) to the switch circuit (12), regardless of whether it is outside the signal.
The signal is supplied to the video reproduction processing circuit (14) through the signal line of the reproduction amplifier (13).

Therefore, the signal Sv is always subjected to peaking correction in the amplifier (11A) before being supplied to the processing circuit (13).

In addition, the PCM audio signal S band is generated by the head (IA), but when the head (IA) is scanning sections PREM and PCMA of the L mode and N mode tracks (2A). If there is, sh-“1”, so the reproduced signal SA is supplied to the equalizer circuit (32) through the signal line of the amplifier (53A)→switch circuit (52A)→switch circuit (31).

Therefore, at this time, the signals PREM and PCMA being reproduced from the sections PREM and PCMA are supplied to the equalizer circuit (32) without causing group delay distortion.

Further, if the head (IA) is scanning the section MRGN of the track (2A), S-=゛0“
Therefore, the reproduced signal SA is sent to the amplifier (IIA)
→Switch circuit (52A)→Switch circuit (31) is supplied to the equalizer circuit (32) through the signal line, but the reproduced signal SA at this time is 1/1/1 of the clock frequency.
Since the margin signal MRGN has a frequency of 2, the amplifier (I
After the level is appropriately corrected by the peaking correction of IA), it is supplied to the extraction circuit (36) and used for clock extraction.

Then, the signals Sv, S reproduced by the head (IB)
Similar processing is performed for A as well. The same applies to the PCM audio signal S band RML mode.

In this way, according to this example, since peaking is applied to the multiplexed signal Sv, it is possible to prevent the level of the FM luminance signal SF from decreasing, and therefore, it is possible to prevent deterioration of the image quality.

However, since such peaking is not applied to the original PCM audio data PCM in the S band of the PCM audio audio signal, S group delay distortion of the PCM audio audio signal does not occur, and therefore the error rate may deteriorate. There is no.

According to experiments, in the group delay characteristic shown in FIG. 6C, if the width Δτ of the characteristic waviness is 30 to 40 nsec or less, the error rate can be made sufficiently small.

G3 Third Embodiment FIG. 9 shows another example of a circuit that performs peaking correction only on the multiplexed signal Sv.
) are connected to peaking circuits (51A) and (51B), and these peaking circuits (51A) and (51
Switch circuits (54A) and (54B) are connected in parallel to B).

When the control signal 5I11 is supplied to these switch circuits (54A) and (54B) and SW="1", the switch circuits (54A) and (54B) are turned on.

According to such a configuration, during the period when the multiplexed signal SV is being reproduced by the head (IA), since 5ii="0", the switch circuit (54A) is off, and therefore the head (IA) is reproducing the multiplexed signal SV. The reproduced signal Sv undergoes peaking correction in the amplifier (IIA) and is then supplied to the video reproduction processing circuit (14) through the switch circuit (12) and the reproduction amplifier (13).

The head (IA) also reproduces the PCM audio signal 54, but if the head (IA) is scanning sections PREM and PCMA of the L mode and N mode tracks (28), , SW="l", so the switch circuit (54A) is on and the peaking circuit (54A) is on.
1A) is equivalent to not connected. Therefore, the signal SA reproduced by the head (IA) is supplied to the equalizer circuit (32) without peaking through the amplifier (IIA) and the switch circuit (31).

Therefore, at this time, the signals PREM and PCMA being reproduced from the sections PREM and PCMA are supplied to the equalizer circuit (32) without causing group delay distortion.

Then, the signals Sv, S reproduced by the head (IB)
Similar processing is performed for A as well. The same applies to the PCM audio signal S group RML mode.

In this way, also in this example, it is possible to apply peaking to the multiplexed signal Sv to prevent a decrease in the level of the FMR degree signal SF, and therefore, it is possible to prevent deterioration of image quality.

However, since such peaking is not applied to the PCM audio signal S group and the original PCM audio audio data PCM, delay distortion of the PCM audio signal S group does not occur, and therefore the error rate may worsen. There is no.

G4 Other Embodiments Note that in the NRML mode, the short wavelength of the PCM audio signal S is not as short as in the L mode or N mode, so the group delay is calculated by applying peaking correction to the PCM audio signal. The distortion may be allowed and the peaking correction may be canceled in the reproduction equalizer circuit (32).

Effects of the Invention According to this invention, when the playback key is pressed, the audio signals R and R are first played from the FM signals SM and SS, and during this time, the setting of the playback equalizer characteristics for the S group of PCM audio audio signals is set. When the setting is completed, the reproduction is switched to the audio signal of the S group of PCM audio audio signals and the reproduction of the R audio signal.

Therefore, even if it takes more than one second to set the equalizer characteristics of the playback equalizer circuit (32) after the playback key is pressed, during the setting, the audio signals R and R from the FM signals SM and SS are output. Therefore, the user does not feel uncomfortable or irritated.

Then, an equalizer circuit (
Immediately after setting the equalizer characteristics in 32),
Since the audio signals of the S group of CM audio audio signals are switched to R, high quality audio signals can be reproduced.

In addition, when the PCM audio signal S group is not recorded, the FM signal needle, audio signals from the SS, and R are automatically output, so the user needs to be aware of the presence or absence of the PCM audio signal S group recording. There is no.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an example of this invention, Fig. 2 is a flow chart of an example of its processing routine, Fig. 3 is a system diagram of an example of a part of it, Part 4 is a characteristic diagram for explaining it, and Fig. 2 is a flow chart of an example of its processing routine. Fig. 5 is a system diagram showing a part of another example of the present invention, Fig. 6 is a characteristic diagram for explaining the same, Fig. 7 is a diagram showing a tiger, Kuformanoto,
FIG. 8 is a diagram showing the relationship between tracks and signals, FIG. 9 is a diagram showing the relationship between systems showing a part of still another example of the present invention, FIG. 10 is a frequency spectrum diagram of a recording/reproducing signal, and FIG. The pattern diagram, Figure 12, is the former of the recording/reproducing signal.
FIG. 13 is a characteristic diagram showing the magnetic characteristics of the magnetic tape. (IA) and (IB) are rotating magnetic heads, (2) are magnetic tapes, (3) are system controllers, (4) are tape sensors, (7) are operation keys, (IIA) and (11B) are head amplifiers. , (14) is a video playback processing circuit, (21
M), (21S) are band pass filters, (23M),
(23S) is an FM demodulation circuit, (24) is a matrix circuit, (25) is a sinch circuit, (32) is a reproduction equalizer circuit, (33) is a level comparison circuit, (34) is a DC component detection circuit, (35 ) is a D flip-flop, (36)
is a clock extraction circuit, (37) is a demodulation circuit, (38) is a reproduction processing circuit, (39) is a D/A converter, (40)
is a PCM mode discrimination circuit, (41) is an equalizer amplifier, (42L), (42N), (42R) is a band pass filter, (43L), (43N), (43R) is a detection circuit, (44L), ( 44N), (44R) are waveform shaping circuits, (51A), (51B) are peaking circuits, (1
00) is a reproduction processing routine, (321) is an equalizer amplifier, (322) is a delay circuit, (323) is a level comparison circuit, and (324) is a variable attenuator circuit.

Claims (1)

[Claims] An FM luminance signal modulated by a luminance signal, an FM audio signal modulated by an audio signal, and a PCM audio signal modulated by the audio signal are extracted from a magnetic tape on which the audio signal is recorded. and a VTR for reproducing the luminance signal, comprising: a rotating magnetic head for reproducing the FM luminance signal, the FM audio signal, and the PCM audio signal from the magnetic tape; and a rotating magnetic head for reproducing the FM luminance signal, the FM audio signal, and the PCM audio signal from the magnetic tape; a reproduction equalizer circuit that performs equalizer processing; an FM demodulation circuit that demodulates the audio signal from the reproduced FM audio signal; a circuit that demodulates the audio signal from the PCM audio signal from the reproduction equalizer circuit; The audio signal demodulated from the audio signal and the PC
and a switch circuit for selectively extracting the audio signal demodulated from the FM audio signal, and at least during the period when the equalizer characteristics of the reproduction equalizer circuit are set, the audio signal demodulated from the FM audio signal is The VTR is configured to take out a signal from the switch circuit, and when setting of equalizer characteristics of the reproduction equalizer circuit is completed, take out the audio signal demodulated from the PCM audio signal from the switch circuit.