JPS61294656A - Tape recorder - Google Patents

Abstract

PURPOSE:To keep a relative speed between a rotary head and a tape constant by detecting the specific signal frequency of a signal reproduced by the rotary head, and controlling the rotating speed of a drum so that the specific signal frequency has an invariably specific value. CONSTITUTION:A signal converted to a TTL level by the 2nd waveform shaping circuit 5b is inputted to an f2 frequency detecting circuit 8 and an f3 frequency detecting circuit 9 to detect an f2 signl and an f3 signal. An f1 signal is recorded next to the f2 signal and the f3 signal without fail, so when either of the f2 or f3 signal is detected, the frequency f1 is already counted and the counted value of an f1 frequency counter 6 is latched in a digital comparator 7 through an OR gate 10 with the output signal of the f2 frequency detecting circuit 8 or f3 frequency detecting circuit 9. Then, the latched counted value is compared with a reference value to output correction data corresponding to the difference, and the rotating speed of the drum is controlled on the basis of the output value to make the relative speed between the rotary head 2 and tape 2 constant.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a helical scan type tape recorder, and when performing high-speed playback, the relative speed between the rotary head and the tape is kept constant, and the tape recorder is accurately positioned on the tape. The present invention relates to a tape recorder that can read recorded signals.

[Prior Art] Conventionally, when a helical scan type cheap recorder is set to high-speed playback mode, a dedicated fixed head is used, and the tape running speed is controlled to be constant based on the detection signal from this circumferential head. The rotational speed of a drum equipped with a rotating head is changed in accordance with the tape running speed and the tape running direction, so that the relative speed between the rotating head and the tape is kept constant.

[Problems to be Solved by the Invention] The conventional helical scan type tape L-:I-)j uses a dedicated fixed head as described above.
The configuration of the tape running system becomes complicated, and two means are required to control the tape running speed and to determine the rotational speed of the drum in order to keep the relative speed constant.

This invention was made to solve the above-mentioned problems, and it is possible to control the relative speed between the rotating head and the tape during high-speed playback by using the playback signal from the rotating head, without using a dedicated fixed head. The purpose is to provide a tape recorder that can be kept constant.

[Means for Solving Problem 1m] The helical scan type tape recorder according to the present invention extracts an arbitrary constant frequency signal calyx from the reproduction signal of the rotating head, and adjusts the rotation of the drum so that the frequency becomes constant. It controls the speed.

[Operation] In this invention, since a specific frequency component is extracted from the reproduction signal of the rotating head, the relative speed between the rotating head and the tape can be kept constant without using a dedicated fixed head, and the tape The configuration of the driving system has been simplified.

[Example] Before explaining the present invention in detail, the principle of the present invention will first be described.

Helical scan tape recorders do not use a fixed head, but use the signals recorded on the tape to form a signal for tracking tracks on the tape, that is, a tracking error signal, and use this to perform tracking. Auto TrackFollowing (
Some devices employ the ATF method (hereinafter referred to as ATF). An example of this is a rotary head digital audio tape recorder (hereinafter referred to as R-D) that records and plays back audio signals.
AT), and its track pattern is as shown in FIG. The signal for performing ATF is recorded in the shaded area of Figure 2 (the difference in the angle of the shaded line indicates the difference in recording azimuth), and the details of the recording pattern are as shown in Figure 3. . As shown in FIG. 3, signals of four types of frequencies from fl to f4 are recorded in the ATF signal recording area. Note that this invention
This is not intended to focus on the TF method, and how tracking is performed using these signals is well known, so a detailed explanation of the operation will be omitted, and this R-DAT will be played back normally. Then, since the relative velocity between the head and the tape for one rotation is a predetermined value, the ATF signals f1 to f
4 is a predetermined frequency, but as the running speed of the tape is changed, the relative speed between the rotary head and the tape becomes different, and as a result, the frequencies of the ATF signals fl to f4 also change.

This invention focuses on the above, detects the frequency of the ATF@ signal, and detects the relative speed deviation between the rotating head and the tape.
The aim is to correct the deviation by controlling the rotational speed of the drum.

An embodiment of the present invention will be described below with reference to FIG. Figure 1 shows the circuit configuration of the embodiment.
The signal recorded in 1) is reproduced by a rotating head (2) and amplified by a head amplifier (3). The output signal of the head amplifier (3) is! A frequency discriminator (low-pass filter or band-pass filter) (4) that passes only the 1-frequency signal, and a 0-frequency discriminator that is input to the second waveform shaping circuit (5b) (signals that have passed 0 are input to the first The signal is input to the waveform shaping circuit (5a), where it is converted to a TTL level signal, and transmitted to the next stage f1 frequency counter (8), where the f1 signal frequency is counted.

On the other hand, the signal converted to the TTL level by the second waveform shaping circuit (5b) is input to the f2 frequency detection circuit (8) and the f3 frequency detection circuit (8), where the f2 signal and f
Detection of three signals is performed. As shown in the recording pattern in Figure 3, the f1 signal is always recorded next to the f2 or f3 signal, so by the time either the f2 or f3 signal is detected, the f1 signal frequency has already been counted. The output signal of the f2 frequency detection circuit (8) or the f3 frequency detection circuit (9) is used to perform an OR game) (1
0), the count value of the f1 frequency counter (ill, ) is latched into the digital humpator (7). At this time, the f1 signal will be reproduced by the reverse azimuth head, but its frequency is sufficiently low and will not be affected much by the azimuth effect, causing no problem.

The digital comparator (7) compares the preset reference value (fl signal frequency) with the latched count value, and data for correcting the drum rotation speed according to the difference is sent to the digital adder (11). ) will be communicated to. The digital adder (11) is a component of the speed control servo loop that controls the rotational speed of the drum.Rotational speed deviation data is also input here, and the data is added to the aforementioned rotational speed correction data to generate a low-pass signal in the first stage. PWM output is provided to the filter (12). The low pass filter (12) is PW
It smoothes the M signal and converts it into an analog signal,
This signal drives the drum motor (10) via the motor drive amplifier (!3).

With the above operation, f is played back by the 5-rotation head (2).
The rotational speed of the drum is controlled so that the signal frequency is always at a predetermined frequency, and the rotation and relative speed of the head and tape are kept constant.

[Effects of the Invention] As described above, according to the present invention, since the specific signal frequency of the signal reproduced from the rotary head is detected and the rotation speed of the drum is controlled so that it always becomes a predetermined value, The relative speed between the rotating head and the tape can be made constant, and signals can be read out accurately even when the tape is running at high speed. Furthermore, since a dedicated fixed head is not used, the tape running mechanism has the advantage of being simpler in configuration.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a circuit configuration of an embodiment of a tape recorder according to the present invention, FIG. 2 is a diagram showing a track pattern of an R-DAT, and FIG. 3 is a detailed diagram of a recording pattern of an ATF signal. (2)... Rotating head, (4)... Frequency discriminator,
(5a), (5b)... Waveform shaping circuit, (8)...
...Frequency counter. (7)...Digital comparator, (8), (9
)...Frequency detection circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A helical scan type tape recorder, which includes a frequency discriminator that passes only a certain low-frequency signal component included in the signal reproduced by the rotary head, and converts the output signal of the frequency discriminator into a TTL level signal. A first waveform shaping circuit for converting, a frequency counter that receives the output signal of the first waveform shaping circuit and counts the frequency of the low frequency signal, and inputs the reproduced signal from the rotary head.
a second waveform shaping circuit that converts the signal into a TL level signal; a first waveform shaping circuit that inputs the output signal of the second waveform shaping circuit and independently detects the other two types of frequency components included in the reproduced signal; A second frequency detection circuit and a value counted by the frequency counter based on each output of the first and second frequency detection circuits are latched, and this latched count value is compared with a reference value. and a digital comparator that outputs correction data according to the difference, and the tape is characterized in that the rotational speed of the drum is controlled based on the output of the digital comparator so that the frequency of the low frequency signal becomes a predetermined value. recorder.