KR970006806B1 - Drum phase auto-control device of vcr - Google Patents

Abstract

a means which comprises a flip flop(10) and an AND gate(20), and generates a clear signal at the time when drum phase sensing signal is generated; a counter(30) counting a clock by being initialized as the generation period of the clear signal; a RF detector(40) detecting the interval of signal record from a RF signal read through a head; a micom(50) adjusting time delay data by analyzing the state of the RF detection signal and a comparison signal; and a comparator(60) comparing a count signal with time delay data and applying as a drum switching phase adjusting signal to the micom(50).

Description

Automatic Drum Phase Adjusting Device and Method of Tape Recording and Reproducing Machine

1 is a conventional circuit diagram.

2 is a circuit diagram of the present invention.

3 is an operational waveform diagram of FIG.

4 is a flow chart of the present invention.

* Explanation of symbols for main parts of the drawings

10: flip-flop 20: endgate

30: counter 40: RF detector

50: micom 60: comparator

The present invention relates to an apparatus and method for adjusting a drum phase of a tape recording / reproducing apparatus. In particular, the drum phase is tracked by tracking a time difference from the point of time at which the drum phase detection signal is generated to the point of time at which the drum switching signal is converted. The present invention relates to an apparatus and a method capable of automatically adjusting.

In general, a tape recording / reproducing apparatus records data on a tape or plays back recorded data through a drum using a rotating head method.

FIG. 1 is a configuration diagram of a conventional drum phase adjustment device. When the drum phase detection signal generation unit 1 generates a drum phase detection signal as shown in (2a), power supply voltage VCC is applied to the capacitor C at two time points. The charging is started, and the comparator 3 compares the voltage level charged in the capacitor C with a reference voltage generated by the reference voltage generator 2 as a comparison signal.

Therefore, the comparator 3 generates a low signal as in (2C) at the moment when the charging voltage as in (2b) becomes larger than the reference voltage. The output of the comparator 3 is applied to the drum switching phase adjuster 5 and is inverted through the inverter IG to turn on the switch SW. Therefore, the voltage charged in the capacitor C is discharged through the switch SWI, and the phase of the drum switching signal is determined during the charging time of the capacitor C.

However, the phase of the drum switching signal should be adjusted to a starting point and a constant phase of the RF signal reproduced from the head to the actual tape. Since the charging time for determining the drum switching phase signal is changed, the variable resistance (VR) is used to manually adjust the phase. It had to be adjusted, and there was a problem that the phase of the drum switching signal was changed by causing a change in the charging time according to the temperature characteristics of the capacitor and the resistor and the prolonged use.

Accordingly, an object of the present invention is to provide an apparatus and method for automatically adjusting the drum phase by the time difference between the RF detection time and the time difference between the generation of the drum phase detection signal and the conversion time of the drum switching signal in the tape recording / reproducing apparatus. In providing.

Hereinafter, the present invention will be described in detail with reference to the drawings.

2 is a block diagram of the present invention, comprising a flip-flop 10 and an end gate 20, means for generating a clear signal at the time of occurrence of a drum phase detection signal, and a predetermined clock which is initialized with a generation period of the clear signal. A counter 30 for counting the signal, an RF detector 40 for detecting the presence or absence of signal recording from the RF signal read through the head, and the state of the RF detection signal and the predetermined comparison signal to analyze time delay data. And a comparator 60 which compares the count signal with the time delay data value and applies it as a drum switching phase adjustment signal to the microcomputer 50 at the same time.

3 is a waveform diagram illustrating operations of each part of FIG. 2.

4 is a flow chart of the present invention, a first process of measuring time at the time of occurrence of the drum phase detection signal, a second process of comparing the measurement time value of the first process and the delay time value of the drum phase adjustment signal; And a third step of measuring a time from the time when the measurement time value is greater than the delay time value in the second process to the detection time of the RF signal, and a fourth process of subtracting the abnormal time value from the measurement time value of the third process. And a fifth process of adjusting the time delay value of the new drum phase adjustment signal by adding the subtraction time value of the fourth process to the delay time value of the drum phase adjustment signal of the previous state.

Based on the above configuration, the present invention will be described in detail with reference to FIGS.

In a tape recording / playback device using a rotating head, the head mounted on the drum needs to control the rotation speed and phase of the drum in order to record / play the signal in the correct phase. To this end, the drum phase is sensed by detecting the drum rotation. The period and phase are controlled by generating a drum switching signal from the signal. Since the phase of the drum switching signal is provided to the system on the basis of the point of time when the head is located at the beginning of the track on the tape, the drum switching signal must be accurately adjusted to a constant phase with the point of time when the head is located at the beginning of the track.

When the drum phase detection signal generated as (N1) by the rotation of the drum is applied to the input terminal of the flip-flop 10, it is outputted as (N3) in synchronization with the clock as (N2). At this time, the AND gate 20 logically multiplies the output of the flip-flop 10 such as N3 and the drum phase detection signal such as N1 to generate a clear signal of the counter 30 such as N4. Therefore, the counter 30 is cleared by the output of the AND gate 20 such as (N4) to start counting the clock such as (N2) again at the time of drum phase detection signal generation.

The output of the counter 30 is applied to the comparator 60 and compared with the time delay data Td equal to the initial data set (N8) in the microcomputer 50, and the output of the counter 30 is compared with the time delay data. If it becomes larger than Td, the output of the comparator 60 generates a drum switching phase adjustment signal in a high state. The output of the comparator 60 is output to the drum switching signal generator (not shown) and fed back to the microcomputer 50.

At this time, the microcomputer 50 starts the time at the time when the drum switching phase adjustment signal such as (N9) becomes high until the time when the RF signal received through the RF detector 40 becomes high as (N6). Measure the time. Thereafter, the microcomputer 50 subtracts the ideal set value from the measured data as described above, and then adds the subtracted data to the drum switching adjustment time data Td in the previous state to obtain the time delay data of the comparator 60 ( Set to Td) and output. Therefore, it can be seen that the time delay data Td is continuously reset according to the count value and the state of the RF detection signal so that the phase of the drum switching signal is automatically adjusted.

Looking at the process of automatically adjusting the phase of the drum switching signal with reference to Figure 4, in step (A) checks the occurrence of the drum phase detection signal, and when the drum phase detection signal generation (B) the counter 30 At the time of clearing and the drum phase detection signal is generated, the counter 30 starts recounting the clock. After that, the microcomputer 50 supplies the time delay data Td to the comparator 60, and the comparator 60 compares the time delay data with the coefficient data. At this time, the microcomputer 50 analyzes the output of the comparator 60 and checks the count data is greater than the time delay data. When the count data is larger, the microcomputer 50 initializes the measurement time data in step (D).

Then, the microcomputer 50 performs steps (E) and (F) to increase the measured data until the RF detector 40 recognizes the signal recording, that is, until the RF detector 40 generates a high signal. When the RF detection signal is generated as a high signal, step (G) is performed to subtract abnormal time data from the measurement time data.

Subsequently, the subtraction data Terr obtained in step (G) is added to the time delay data Td of the previous state in step (H) to set a new delay data, and then the step (A) is returned in preparation for the next state. Goes. By repeating the above procedure, the phase of the drum switching signal is automatically adjusted ideally.

As described above, instead of individually adjusting the phase of the drum for each system, it is possible to automatically adjust the phase of the drum switching signal accurately by automatically tracking the delay time until the drum phase detection signal is generated. .

Claims (2)

An automatic drum phase adjusting device of a tape recording / reproducing apparatus, comprising: a flip-flop (10) and an end gate (20), and means for generating a clear signal at the time of generating a drum phase detection signal, and initializing at a clearing cycle of the clear signal; A counter 30 for counting a predetermined clock, an RF detector 40 detecting a presence or absence of signal recording from an RF signal read through the head, and a time delay by analyzing the states of the RF detection signal and a predetermined comparison signal. A tape recording comprising a microcomputer 50 for adjusting data, and a comparator 60 for comparing the count signal with the time delay data value and applying the same as a drum switching phase adjustment signal to the microcomputer 50. Automatic drum phase control device for the player. An automatic drum phase adjustment method of a tape recording / playback apparatus, comprising: a first step of measuring a time at the time of occurrence of a drum phase detection signal, and comparing a measurement time value of the first step with a delay time value of the drum phase adjustment signal; In the second process, the third process of measuring the time until the detection time of the RF signal when the measurement time value is greater than the delay time value in the second process, and the abnormal time value is subtracted from the measurement time value of the third process And a fifth process of adjusting the time delay value of the new drum phase adjustment signal by adding the subtraction time value of the fourth process to the delay time value of the drum phase adjustment signal of the previous state. Automatic drum phase adjustment method for tape recorder.

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