KR900005140Y1 - Piloting circuit of video tape playing quantity - Google Patents

Abstract

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Description

Tape remaining display circuit

1 is a block diagram of a tape remaining amount display circuit according to the present invention.

2 is a concrete circuit diagram of FIG.

3 is an operation timing diagram of each part of FIG.

4 is a flow chart of the control microcomputer.

* Explanation of symbols for main parts of the drawings

10: supply reel rotation device 20: reel rotation detection circuit

30: waveform shaping circuit 40: differential circuit

50: division circuit 60: clock generation circuit

70: counter D / A: conversion circuit

90: sample and hold circuit 100: control microcomputer

110: display circuit

The present invention relates to a circuit for displaying the remaining amount of tape in the tape drive device, and more particularly to a circuit that can display the remaining amount of the tape through the display device in the record mode (Play mode) or play mode (Play Mode) will be.

In a conventional audio or video system, mechanical or electronic counters were used to indicate the remaining amount of tape, but they were displayed as the tape rotated. It was to indicate the amount recorded or reproduced.

Therefore, it was difficult to calculate how much tape remained in the system in operation, which caused a lot of inconvenience because the user had to roughly estimate the amount of tape that was not recorded or played during recording or playback in record or recording mode. Had caused.

Accordingly, an object of the present invention is to provide a circuit that detects a rotation period of a supply reel in a recording or reproducing mode in a tape drive and then calculates and displays the remaining amount of tape.

The present invention for achieving the above object analyzes the state of the operation mode (recording or playback mode), the tape use mode (SP, LP, SLP) and tape usage standards, and the remaining tape standards according to the tape usage standards in the internal memory A tape remaining amount display circuit of a tape drive device having a control microcomputer storing data and a display circuit displaying the remaining amount of tape time by the control micom, wherein the rotation period of the supply reel is detected and converted into an electrical signal. A reel rotation detection circuit, a waveform shaping circuit for shaping the output of the reel rotation sensing circuit into a square wave, a differential circuit for converting a rotation period signal of the waveform shaping circuit into a pulse signal, and dividing and resetting the output of the differential circuit A division circuit for generating a signal, a clock generation circuit for generating a clock signal of a predetermined frequency, and a reset signal of the division circuit And a counter for counting the clock during a reset signal generation period, a D / A conversion circuit for converting the output of the counter into an analog signal, and a sample and hold output of the D / A conversion circuit. And a sample and hold circuit that maintains a maximum value for the corresponding rotation period of the memory. The control microcomputer inputs the output of the sample and hold circuit, which is varied according to the rotation of the supply reel, as a comparison data for calculating the remaining tape. After comparing with the reference data of the characterized in that the operation to output the display circuit to calculate the remaining tape data in accordance with the tape use mode.

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

1 is a block diagram of a tape remaining amount display circuit according to the present invention, a reel rotation device 10 for driving a supply reel, and a reel rotation detection circuit 20 for detecting a rotation period of the supply reel and converting it into an electrical signal. And a waveform shaping circuit 30 for shaping the output of the reel rotation sensing circuit 20 into a square wave, a differential circuit 40 for converting a rotation cycle signal of the waveform shaping circuit 30 into a pulse signal, A division circuit 50 for dividing the output of the differential circuit 40 to generate a reset signal, a clock generation circuit 60 for generating a clock signal of a predetermined frequency, and a reset signal of the division circuit 50; A counter 70 for counting the clock during a reset signal generation period, a D / A conversion circuit 80 for converting the output of the counter 70 into an analog signal, and the D / A conversion Sample and hold the output of circuit 80 so that the corresponding rotation of the supply reel Sample and hold circuit 90 that maintains the maximum value during the cycle, operation mode (record or playback mode), tape use mode (SP, LP, SLP) and tape use specifications (T-30, T-60, T) A control microcomputer for analyzing the mode states of -120, T-160, etc. and calculating the remaining amount of tape by comparing the output of the sample and hold circuit 90 with reference data for the remaining amount of tape stored in the internal memory. 100 and a display circuit 110 for displaying the remaining tape time under the control of the control microcomputer 100.

When the present invention is described based on the above-described configuration, the supply reel is rotated by the supply reel rotating device 10, and the reel rotation detection circuit 20 converts the mechanical rotation of the supply reel into an electrical signal. When the electrical signal is input to the waveform shaping circuit 30, it is shaped into an accurate square wave, and the square wave signal is input to the soap circuit 40 and converted into a differential pulse. The differential pulse is input to the division circuit 50 and converted into a two division signal in which a negative component is removed to determine a reset period. At this time, the counter 70 for inputting the clock signal and the divided signal of the clock generation circuit 60 counts the clock signal while the next reset signal is input after the reset signal is inputted, thereby generating the binary signal. Data is applied to the D / A conversion circuit 80. The D / A conversion circuit 80 then converts the binary digital signal into an analog signal of an appropriate level.

The sample and hold circuit 90 inputting the output of the D / A conversion circuit 90 samples the maximum value of the analog signal and maintains the value, and when the next maximum value is input, the next maximum value is sampled again to obtain the value. Will be held.

Up to now, the above-described state is a state in which the supply reel disk is continuously rotated, and as the rotation period decreases gradually as time passes, the generation cycle of the reset pulse becomes faster and the clock counted by the counter 70. The number of pulses becomes small, which causes the maximum value of the sampling and hold circuit 90 to gradually decrease. When the signals are input to the control microcomputer 100 over time, the control microcomputer 100 checks the power signal and the operation mode (recording mode or playback mode) of the system, and the standard play ( Standard play: hereinafter referred to as SP). Long Play (hereinafter referred to as LP). Check which mode is selected from the state of Super Long play (hereinafter referred to as SLP), and it is 30 minutes (T-30), 60 minutes (T-60), 120 minutes T-120) and 160 minutes (T-160), after checking the input signal, the pre-programmed software sets the reference data set in accordance with the new tape standard that stores the output of the sampling and hold circuit 90 in the internal memory. Calculate the remaining tape time by comparing with. Then, when the remaining tape time is calculated, the control microcomputer 100 converts the remaining tape data into hour and minute data and outputs it to the display circuit 110.

FIG. 2 is a detailed circuit diagram of the block diagram of FIG. 1 according to the present invention, in which a supply reel rotating device 10 including a supply reel disk 11, a reflector 12, and a power supply terminal VCC are provided with a resistance ( In parallel to R1 and R2, connect resistor R1 to the anode of the photo-interrupter (PI) light-emitting diode (LED1), ground the cathode, and connect resistor (R2) to the photointerrupter (PI) Reel rotation sensing circuit 20 connected to the collector of transistor PTr1 and the emitter grounded, and the collector of port transistor PTr of photointerrupter PI are connected to the base of transistor Q1, and the power supply terminal ( VCC) connects resistor R3 to the collector of transistor Q1, the emitter is connected to the ground shaping circuit 30, and capacitor C1 to the collector of transistor Q1, and resistor R4 in parallel. ) Connects differential circuit 40 and resistor R5 to anode of diode D1 and A divider circuit 50 for outputting the draw, a clock generation circuit 60 for generating a clock of a predetermined frequency, and an output of the clock generation circuit 60 and the output of the frequency division circuit 50 are inputted in reset pulse period units. The counter 70 for counting the clock number, the D / A conversion circuit 80 for converting the output of the counter 70 into an analog signal, and the capacitor C2 are connected to the anode of the diode D2, and the diode ( A sample and hold circuit 90 in which the cathode of D2) is connected in parallel to the capacitor C3 and the resistor R6, and the capacitor C3 and the resistor R6 are grounded, and as a one chip micom to the internal memory. It stores the reference data for the remaining tape time according to the tape standard, and analyzes the operation mode (recording or playback mode) signal generated through the AND gate (G1) and simultaneously uses the tape through the input / output port (P3-P9). (SP, LP, SLP) and Tape Standard Time (T-30, T-60, T-120, T-160) When the output of the sample and hold circuit 90 is input, the control microcomputer 100 for calculating the remaining data according to the corresponding tape specification time and the use mode, and converting the converted data into the display data and the control microcomputer 100, And a display circuit 100 for displaying the remaining tape amount according to the output.

3 is an operation timing diagram of each part with respect to the specific circuit diagram of the embodiment of FIG. 2, FIG. 3A is a timing diagram of the reel rotation sensing circuit 20, and FIG. 3B is a timing diagram of the waveform shaping circuit 30. 3c is a timing diagram of the differential circuit 40, 3d is a timing diagram of the frequency divider circuit 50, 3e is a timing diagram of the counter 70, and 3f is a timing diagram of the D / A conversion circuit 80. 3g is a timing diagram of the sample and hold circuit 90. As shown in FIG.

4 is a process flowchart of the control microcomputer 100.

2 is a detailed circuit diagram of an embodiment according to the present invention with reference to the operation timing diagram of FIG.

First, the supply plate 11 is fabricated and pasted with a reflecting plate 12 which is provided by separating the absorption surface and the reflection surface of the optical signal.

When the set starts to operate in the playback mode or the recording mode, the surviving disc 11 is rotated, which causes the reflector 12 to rotate in conjunction. Then, the light emitting diode LED1 of the photointerrupter PI is turned on at the reflecting surface of the reflecting plate 12 and turned off at the absorbing surface, and is applied to the base of the phototransistor PTR1 of the photointerrupter PI, thereby causing the phototransistor ( PTR1) is turned on and off to invert and amplify the signal of the light emitting diode LED1 to the collector terminal as shown in FIG. 3a.

The inverted-amplified signal of the photointerrupter PI may adjust the interval of the pulse according to the ratio of the reflecting surface and the absorbing surface of the reflector 12.

Since the inverted-amplified signal as shown in FIG. 3a is input to the base of transistor Q1 to turn on and off transistor Q1, the output of the collector terminal is incomplete square wave of inverted-amplified photointerrupter PI as shown in FIG. 3b. Inverted and amplified to a complete square wave. The square wave signal is input to the differential circuit 40 of the capacitor C1 and the resistor R4 and is generated as a differential pulse suitable for the reset pulse. The differential period is generated by the time constant of the resistor R4 and the capacitor C1. A timing diagram relating to the differential pulse capable of adjusting is shown in FIG. 3C. The differential pulse passes through the resistor R5 and the diode D1, and the negative pulse waveform is removed and only the positive pulse waveform is output to divide the differential pulse as shown in FIG. The divided signal is input to the reset pulse of the counter 70, and the generation period of the reset pulse is generated in proportion to the remaining amount of the tape wound on the supply reel. In other words, if the amount of tape wound on the supply reel is large, the number of occurrences of the reset pulse is small. If the amount of tape is small, the frequency of occurrence is frequent.

The counter 70 inputs the clock pulse of the clock generation circuit 60 as the clock terminal, counts the clock pulse as shown in FIG. 3e after the reset pulse is input, and counts the binary data counted when the next reset pulse is input. 0 is set to 0 and counting is restarted for the clock pulse. Therefore, the counting of the clock pulse is continued according to successive reset pulses. Therefore, the counter 70 performs a tape according to the conversion of the amount of tape wound on the supply reel. The comparative data for calculating the remaining amount will be output continuously. The D / A conversion circuit 80 converts and outputs the digital signal of the counter 70 into an analog signal of an appropriate level as shown in FIG. 3f and outputs the analog signal to the sample and hold circuit 90. The output of the D / A conversion circuit 80 is removed from the DC component while passing through the capacitor (C2), in the envelope detector (Envelope cletector) consisting of a diode (D2), a capacitor (C3), a resistor (R6) Capacitor C2 charges rapidly to the peak voltage when diode D2 is forward biased, and capacitor C2 is pulled through resistor R6 when output voltage of D / A conversion circuit 80 drops past its maximum value. Discharge slowly. Therefore, through the sample and hold circuit 90, an envelope of counting data is detected as shown in FIG. Therefore, the sampling and hold circuit 90 has a function of sampling the maximum value of the input signal and maintaining the maximum value of the next signal.

At this time, the rotation period of the supply reel gradually decreases as time passes, and as the amount of tape decreases, the electrical signal detected by the reel rotation decreases, and the differential pulse of the differential circuit gets faster, so the period of the reset pulse becomes smaller. You lose. Accordingly, the amount of counting of the clock pulses that the counter 70 can count during the reset period is also reduced, and the analog signal of the D / A conversion circuit 80 that converts the binary data into an analog signal is also small, thereby eventually holding the sample and hold. The maximum value of the circuit 90 also becomes small. When the output of the sample and hold circuit 90 is continuously input to the control microcomputer 100, the control microcomputer 100 displays the remaining amount in comparison with the reference data of the internal memory which is calculated and recorded for each tape standard time in advance. do.

The control microcomputer 100 is a well-known one-chip microcomputer having a CPU, a ROM, a RAM, an input / output port, an A / D converter, and the like, and performs a function for calculating the remaining amount of tape.

Here, the process of displaying the remaining tape time in the control microcomputer 100 will be described in detail with reference to FIG. 4.

First, the front panel of the tape drive unit has a switch indicating tape specifications (T-30, T-60, T-120, T-160), and a tape usage mode (SP, LP, SLP). There is a switch, through which the user can specify the standard and mode of use of the tape. Only ports for one tape specification and mode of use are then "high" while all other ports are "low". In addition, in the ROM inside the control microcomputer 100, data obtained by calculating an average value through experiments for various tape standards are stored as reference data.

When the recording or playback mode is entered, a "high" signal is generated from the system controller and input to the AND gate G1. When the power is "on" to the other input of the AND gate G1, the "HI" signal is generated. Signal is applied. Therefore, the control microcomputer 100 receives the "high" signal through the port P2 and performs a function for displaying the remaining tape amount. At this time, when the output voltage of the sample and hold circuit 90 is received at the port P1, the output voltage of the sample and hold circuit 90 is converted into a digital value, and the ports P6-P9 are checked to analyze the tape specifications currently in use. After recognizing the tape standard, the reference data of the corresponding tape standard stored in the ROM is read and compared with the data read through the sample and hold circuit 90 to calculate the remaining data of the tape. When the remaining data of the tape is obtained, the remaining data of the tape (SP, LP, SLP) are analyzed through the port (P3-P5) to calculate the remaining data of the tape that can actually record or play in the use mode. . In this case, since the display circuit 110 is a digit display device including 7-segment type LEDs, the calculated remaining amount of tape data is converted into 7-segment type hour and minute data and output to the port 10. do.

Then, the display circuit 110 displays the remaining time of the tape remaining by the output of the control microcomputer 100.

The tape drive is based on the VTR. If the audio product is used, the tape mode (SP, LP, SLP) is not required and the tape specifications are different. Can be.

As described above, the remaining amount of tape can be displayed with time, so that the user can visually check the remaining amount of tape so that the user can conveniently use an audio or video product, and the user can select a desired program during playback. It is easy to find by calculating the time of, and in particular, by calculating the remaining amount of the tape being recorded, there is an advantage that a perfect recording can be performed by pre-calculating the amount of tape to be recorded when recording an important or necessary part.

Claims (1)

The control microcomputer 100 analyzes the operation mode (recording or playback mode), the tape usage mode (SP, LP, SLP), and the tape usage specification, and stores remaining reference data according to the tape usage specification in the internal memory. In the tape remaining amount display circuit of the tape drive device having a display circuit 110 for displaying the remaining time of the tape by the control microcomputer (100), the reel for detecting the rotation period of the supply reel and converts it into an electrical signal The rotation detection circuit 20, the waveform shaping circuit 30 for shaping the output of the reel rotation sensing circuit 20 into square waves, and the differential circuit for converting the rotation period signal of the waveform shaping circuit 30 into a pulse signal. 40, a division circuit 50 for dividing the output of the differential circuit 40 to generate a reset signal, a clock generation circuit 60 for generating a clock signal of a predetermined frequency, and the division circuit 50 By reset signal A counter 70 which is vaporized and counts the clock during a reset signal generation period, a D / A conversion circuit 80 that converts the output of the counter 70 into an analog signal, and the D / A conversion circuit ( A sample and hold circuit 90 for holding and holding the output of the sample 80 to maintain a maximum value during a corresponding rotation period of the supply reel, wherein the sample end is varied according to the rotation of the supply reel in the control microcomputer 100. The output of the hold circuit 90 is input as a comparison data for calculating the remaining amount of tape, and compared with the reference data of the memory to calculate the remaining amount of tape data according to the tape use mode and output the data to the display circuit 110. Tape remaining amount display circuit, characterized in that.