JPH065588B2 - Tape recorder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape recorder suitable for use in high-speed reproduction with a rotary head type PCM tape recorder, for example.

2. Description of the Related Art Conventionally, in a rotary head type tape recorder or the like, a dedicated fixed head (control head) is used in a variable speed reproduction mode, for example, when high-speed reproduction is performed for the purpose of cueing. Servo is applied so that the relative speed of the tape and the drum provided with the rotary head becomes constant by the detection signal. And when recording in advance,
50% control signal for normal servo
Although it is recorded with the duty of,
It is inserted at a duty of about 10 seconds for about 10 seconds, and at the time of reproduction, the difference in the duty of this control signal is detected to perform the cueing.

For example, at the time of high speed reproduction, a reproduction control signal P as shown in FIG. 1A is detected, and the waveform is shaped into a signal waveform with a duty of 50% as shown in FIG. 1B. Even if the servo is applied so that the relative speed of the drum becomes constant, when the cueing pulse Q as shown in FIG. 1A is detected, this is output as a signal with a substantially 20% duty as shown in FIG. 1C. The waveform is shaped into a waveform so that the tape running is stopped.

However, when the dedicated fixed head is used in this way, the structure becomes complicated, and the output level changes depending on the reproduction speed, making it difficult to accurately keep the relative speed of the tape and the drum constant.

SUMMARY OF THE INVENTION In view of the above problems, the present invention uses RF information on a tape to make the relative speed of the tape and the drum (rotating head) constant during high-speed reproduction without using a dedicated fixed head for control. The present invention provides a tape recorder that can be used.

SUMMARY OF THE INVENTION The present invention is, for example, as shown in FIG. 2 and FIG.
In a tape recorder which performs high-speed reproduction by a rotary head (H _A) (H _B), a rotating head (H _A) (H _B) detection means for detecting the signals S ₁ reproduced by (3), which is the detection The signal S ₂ is compared with the threshold level, and the comparison means (5) that outputs the pulse-shaped signal S ₃ each time scanning is performed across the track and the period of the pulse-shaped signal S ₃ are detected,
Cycle proportional signal output means (6) to (9) for outputting an output signal S ₈ proportional to the detected cycle are provided, and the reel driving motor (13) is controlled based on the output signal S ₈ . It is a thing. That is, according to the present invention, the periodical fluctuation between tracks is detected from the output of the rotary head during high-speed reproduction, and the rotation of the reel (motor) is controlled by this detected output so that the relative speed between the tape and the rotary head is constant. In the tape recorder characterized by the above, a dedicated fixed head is not required, and the configuration is simplified.

Embodiment An embodiment of the present invention will be described in detail below with reference to FIGS.

FIG. 2 shows a circuit configuration of the present embodiment. In FIG. 2, a tape (1) as a recording medium is sequentially scanned by a plurality of rotary heads H _A and H _B so that a normal reproduction mode is achieved. As shown in FIG. 3, the heads H _A and H _B alternately scan each signal track T recorded at a predetermined azimuth angle for each field. However, during high speed reproduction, for example, during rewinding, these heads H _A and H _B scan across a plurality of signal tracks T, as indicated by the hatched lines a in FIG. Therefore, at this time, the rotary head H _A ,
When the detection signal from H _B is amplified by the amplifier (2), the RF signal S ₁ as shown in FIG. 4A is taken out at the output side. The shaded area in FIG. 4A represents the area where the actual data information can be read. Then, this signal S ₁ is supplied to the detection circuit (3), where it is rectified and taken out as a signal S ₂ as shown in FIG. 4B. The signal S ₂ is supplied to the waveform shaping circuit (5) through the low pass filter (4), where the threshold level T
_It is compared with _H (see FIG. 4B), and at its output side, a pulsed signal S ₃ having a constant period T ₀ as shown in FIG. 4C is taken out. That is, the fluctuation of the head passing period between tracks is detected. This cycle T ₀ is approximately inversely proportional to the relative speed of the tape (1) during high-speed reproduction and the rotary heads H _A and H _B , and may be set to any value.

The signal S ₃ is supplied to a monostable multivibrator (6), wherein signal S ₃ of the example fourth signal S _4, such as shown in Figure D in synchronism with the rising is formed, further the signal S ₄ is monostable It is fed to the multivibrator (7), where the signal S ₄
For example, the signal S as shown in FIG.
₅ is formed and output. Based on this signal S ₅ , a sawtooth wave signal S ₇ as shown in FIG. 4G is formed in the sawtooth wave signal generation circuit (8) at the next stage. This signal S ₇ is supplied to the sampling and holding circuit (9).

Further, the output signal S _{3 of} the waveform shaping circuit (5) is supplied to the trigger pulse generating circuit (10), and this trigger pulse generating circuit (10) is shown in FIG. 4F in synchronization with, for example, the rising edge of the signal S ₃ . Such a narrow pulse signal S ₆ is generated. This signal S ₆ is supplied as a sampling pulse to the sample and hold circuit (9) via the AND circuit (11), the sawtooth wave signal S ₇ is sampled based on this signal S ₆ , and the output side thereof is provided. , A constant output signal S ₈ as shown in FIG. 4H is taken out. This signal S ₈ is amplified by the drive circuit (12) and then supplied as a drive signal to the reel motor (13) so that the cycle T _{0 of the} signal S ₃ with respect to the reel motor (13) is always constant. Servo is applied. For example, the signal S
_When the cycle T _{0 of 3} becomes smaller, the rotation speed of the reel motor (13) becomes faster. Therefore, the level of the signal S ₈ is lowered. On the other hand, when the cycle T ₀ of the signal S ₃ becomes larger, the reel motor (13) becomes smaller. Since the rotation speed of is slowed down, the signal S ₈ should be raised. As a result, a constant relative speed between the tape (1) and the rotary heads H _A and H _B can be obtained.

The RF signal S ₁ is formed based on this signal S ₁ because its level fluctuates near the start point and the end point where the head runs diagonally on the tape during high-speed reproduction and is unstable. The AND circuit (11) through which the signal S ₆ passes is controlled as follows to avoid such an unstable element.

That is, after the waveform shaping circuit (5), the signal during the instability period of the S ₁ are a plurality of counter in series relationship for the trigger pulse mask so impervious to signal S ₆ (14), is (15) both A counter (14) is provided with an AND circuit (24) in between.
The signal S ₃ from the waveform shaping circuit (5) is supplied to the counter (15), and the output signal (carry) of the counter (14) and the output signal of the waveform shaping circuit (5) to the AND circuit (24) are supplied to the counter (15). It is designed to be supplied through. The output signal of the counter (14) is supplied to the reset terminal R of the flip-flop circuit (16), and the output signal (carry) of the counter (15) is supplied to the set terminal S of the flip-flop circuit (16). It is done like this. The output from the inverting output terminal of the flip-flop circuit (16) is supplied to one input side of the AND circuit (11), and the above-mentioned trigger pulse generation circuit ( The signal S ₆ (trigger pulse) from 10) is supplied. The counter (14) is preset with a predetermined number N ₁ , while the counter (15) is preset with a predetermined number N ₂ . These counters
The set values of (14) and (15) are determined depending on the drum rotation direction and speed and the tape running direction and speed. Therefore,
When the counter (14) counts the signal S ₃ from the waveform shaping circuit (5) by N ₁ , the output of the counter resets the flip-flop circuit (16), and this flip-flop circuit (16)
The inverted output (high level) of the AND circuit (11) opens the gate of the AND circuit (11), while the counter (15) opens the gate of the AND circuit (24) by the output when the counter (14) counts N _1. The signal S ₃ from the waveform shaping circuit (5) is started to be counted from the time point, the flip-flop circuit (16) is set by the output at the time point when N _{2 is} counted, and the AND circuit (11) is set by the inverted output (low level). The gate of is closed, and the extraction of the signal S ₆ is completed. That is, the mask pulse period of the trigger pulse is substantially determined by the set value N ₁ of the counter (14), and the trigger pulse acquisition period is determined by the set value N ₂ of the counter (15). Therefore, the counter (1
While 5) counts up to N _2, the gate of the AND circuit (11) is opened, and the signal S ₇ is sampled by the signal S ₆ passed during that period.

For setting N ₁ and N ₂ for the counters (14) and (15), for example, a plurality of selectors (17) and (18) are provided corresponding to the counters (14) and (15), and further, ROMs (19), (20), and (2) that store count value information corresponding to fast forward (FF) and rewind (REW) for these selectors (17) and (18), respectively.
Provide 1) and (22). And a fast forward command from the terminal (23)
The selectors (17) and (18) are switched by (FF) or the rewind command (), and the corresponding count value information of N ₁ and N ₂ is stored in each ROM (19), (20) and (21), (22). ), And set the counters (14) and (15) respectively. Thus, as described above, instability during fast playback period of the signal S ₁ is removed, signals S ₁ of substantially stable signal S ₃ during
The signal S ₆ thus formed can be taken out as a sampling pulse. In the above embodiment, the case where the servo is applied with the period T ₀ of the signal S ₃ after waveform shaping as a reference has been described, but the level E ₀ of the RF waveform signal S ₁ (see FIG. 4A) is used as a reference. Servo may be applied as (relative speed of tape and head is constant).

As described above, according to the present invention, the fluctuation in the period between tracks is detected from the output of the rotary head during high-speed reproduction, and the rotation of the reel (motor) is controlled by this detected output to control the relative speed of the tape and the rotary head. Since it is set to be constant, a dedicated fixed head used for control in the past is not required, and the configuration is simplified. Also, because the relative output speed is constant due to the constant relative speed between the tape and the rotary head, it is possible to read the information recorded on the tape.
For example, it is extremely useful when used in a variable speed reproduction mode such as a cue and a track interval detection.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the conventional example, FIG. 2 is a system diagram showing one embodiment of the present invention, and FIGS. 3 and 4 are diagrams for explaining the operation of FIG. Is. H _A and H _B are rotary heads, (3) is a detection circuit, (5) is a waveform shaping circuit, (6) and (7) are monostable multivibrators, (8) is a sawtooth wave signal generation circuit, and (9 ) Is the sample and hold circuit,
(10) is a trigger pulse generating circuit, (11) and (24) are AND circuits, (13) is a reel motor, (14) and (15) are counters, (16)
Is a flip-flop circuit, (17) and (18) are selectors, (19),
ROMs (20), (21), and (22) are ROMs.

Claims (1)

[Claims] 1. A tape recorder for high-speed reproduction by a rotary head, wherein detection means for detecting a signal reproduced by the rotary head is compared with a threshold level of the detected signal,
There is provided a comparing means for outputting a pulse-shaped signal each time scanning is performed across the tracks, and a cycle proportional signal output means for detecting a cycle of the output pulse-shaped signal and outputting an output signal proportional to the detected cycle. A tape recorder comprising: a reel driving motor controlled based on the output signal.