KR0128095Y1 - Aft compensation circuit for 8mm tape - Google Patents

Abstract

The present invention relates to an ATF compensation circuit of 8mm tape. When 8mm tape is placed on the deck, the tape type signal (ME / ) And the recording speed signal (LP / ) And the microprocessor receiving the tape type signal ME / MP, select signals Sel1 and Sel2 are output so that the recording pilot signal is input to the amplifier through a low pass filter in the frequency divider. Recording speed signal from (LP / ) And tape type signal (ME / ) Is logically inverted and then inverted by the inverter and input to the amplifier so that the above-mentioned recording pilot signal is selectively amplified (when ME tape or LP recording), and the leveled-up recording pilot signal is mixed with the Y / C signal. By recording on 8mm tape, speed detection by the microprocessor during playback is stabilized.

Description

8mm tape ATF compensation circuit

1 is a waveform diagram of a general reproduction ATF error signal.

2 is a block diagram showing the overall configuration of the present invention.

3 is a diagram and waveform diagram showing a state of generating a recording pilot signal of the present invention.

* Explanation of symbols for main parts of the drawings

1: deck 10: microprocessor

11: key input unit 12: divider

14: low pass filter 15: Oagate

16 inverter 17 amplifier

The present invention relates to an ATF compensation circuit of 8mm tape in an 8mm camcorder or VCR. In particular, the speed of playing 8mm tape is compensated by compensating the recording ATF pilot signal corresponding to the tape recording speed of SP or LP for the tape type of ME or MP. The present invention relates to an ATF compensation circuit of 8 mm tape which eliminates anxiety of detection and has compatibility between sets.

In general, 8mm camcorders or VCRs use MP Particle Tape and ME Evaporated Tape instead of the normal oxide tape used in the VHS (Vide Home System), and the recording speed is also SP (Standard Playing) It is well known that the player selects and uses LP (Long Playing).

MP tapes and me tapes, which are different from one another, vary depending on the manufacturer. However, since the error level is lower in ATF (Automatic Track Finding) reproducing ME tapes by metal deposition than MP tapes by metal particles, the speed of micro tape There is a lot of room for error when detecting.

That is, in 8mm tape, the ATF error level due to the frequency of the difference between the four pilot signals f1 to f4 for the ATF in addition to the recording signal must be maintained at the reference level of 2.5V as shown in FIG. Since the recorded gas oil and ME tape are smaller than 2.5V, a lot of errors occur when performing the speed detection function in the microcomputer.

This means that when recording on a current 8mm camcorder and VCR, the recording pilot signals f1 to f4 are mixed with the Y / C signals without considering the type of tape (ME / MP) and recording speed (SP / LP). Because it is written.

Therefore, there is almost no problem when recording with normal SP and playing back with SP. However, when recording with LP or using ME tape, the ATF error level is lower than the reference level (2.5V) during playback. There was a disadvantage in that the wrong detection occurs frequently.

Accordingly, the present invention provides an 8mm tape ATF compensation circuit that eliminates the instability of speed detection regardless of the type of tape or the recording speed by compensating for the recording ATF pilot signal to be recorded by using ME tape or LP when recording. It is for that purpose.

In order to achieve the above object, the present invention outputs the tape type signal (ME / MP) from the tape judgment switch according to the hole of the tape when 8mm tape is placed on the deck, and the recording speed signal (LP / SP) by the user The microprocessor receiving the tape type signal ME / MP outputs a selection signal Sel1 and Sel2 so that the recording pilot signal is input to the amplifier through a low pass filter in a frequency divider. The recording pilot signal (LP / SP) and tape type signal (ME / MP) are non-sorted and then inverted by the inverter and input to the amplifier so that the above-mentioned recording pilot signal is selectively amplified (when ME tape or LP recording). Therefore, the leveled-up recording pilot signal is mixed with the Y / C signal to be recorded on the 8mm tape, so that the speed detection by the microprocessor during playback is stabilized.

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

2 is a block diagram showing the overall configuration of the present invention, the deck that outputs the tape type signal (ME / MP) according to the hole of the 8mm tape with a tape determination switch (not shown) when the 8mm tape is seated (1 ), A preamplifier (3) for amplifying a Y / C signal picked up from the video head (2) of the deck (1) and containing pilot signals (f1 to f4) for the ATF, and the preamplifier (3). Envelope detector (4) for detecting the envelope waveform for the Y / C signal amplified by the low pass filter and a low pass filter for passing only signals below 200 KHz of the envelope waveform from the envelope detector (4). (5) and four pilot signals f1, f2, and f3 (f4) required for ATF are 102.54 ± 0.1 (KHz), 118.95 ± 0.1 (KHz), 165.21 ± 0.1 (KHz) and 148.69 ± 0.1, respectively. The pilot signal from the reference pilot signal generator 6 and the reference pilot signal generator 6 outputted at (KHz), the signal via the low pass filter 5 Balance modulator 7 for receiving 16KHz (fH) and 46KHz (3fH) corresponding to the difference between the signals and 16KHz and 46KHz waveforms outputted from the balance modulator 7 above. A detector 8 which passes through the 16KHz bandpass filter 8a and the 46KHz bandpass filter 8b, and then passes through the DC detectors 8c and 8d and detects the DC levels of the two signals; A comparator 9 for comparing the two signals output from the two DC detectors 8c and 8d of the output unit 8 and outputting a regenerated ATF error signal (PB ATF error) corresponding to the difference, and from the comparator 9 A microprocessor 10 that receives a tape type signal (ME / MP) from the deck 1 while receiving a playback ATF error signal (PB ATF Error) and controls correction of a recording pilot signal, and a user's option. And a key input unit 11 for outputting a recording speed signal LP / SP to the microprocessor 10, The four pilot signals f1 to f4 are generated by dividing the pulse input from the 5.9 MHz oscillator 13 by the selection signals Sel1 and Sel2 output from the microprocessor 10 to generate the above-mentioned reference pilots. A divider 12 for outputting a square wave to the signal generator 6, a low pass filter 14 for outputting a recording pilot signal output as a square wave from the divider 12 as a recording pilot signal of a sine wave, and The OR gate 15 for ORing the tape type signal ME / MP and the recording speed signal LP / SP output from the microprocessor 10 and the OR signal 15 for inverting the OR signal in the OR gate 15 are inverted. The inverter 16 and the signal inverted by the inverter 16 receive the resistor R3 to the inverted input terminal grounded through the lower R1 while the recording pilot signal is input to the non-inverting input terminal and receives the recording pilot signal. Selectively amplify the recorded file Signal will configured in a mixer 18 with a resistor (R2), the amplifier 17 through the feedback unit to be recorded on the 8mm tape and then mixed on a Y / C signal.

Here, reference numeral 19 is a capstan motor driver for driving the camston motor in accordance with the output of the microprocessor.

The ATF compensation circuit of the 8mm tape of the present invention configured as described above has a tape thickness signal (ME / MP) by the tape judgment switch of the deck (1) when the user inserts and mounts the 8mm tape into an 8mm camcorder or VCR in order to know recording. The recording speed signal LP / SP inputted to the processor 10 and selected by the user through the key input unit 11 is also input.

Here, the tape thickness signal ME / MP recognizes the hole on the back of the tape as the tape determination switch and inputs the ME tape surface H and the MP tape surface L to the microprocessor 10.

In the frequency divider 12 which receives the selection signals Sel1 and Sel2 from the microprocessor 10, the pulses from the 5.9 MHz oscillator 13 are divided to provide four pilot signals f1 to f4. Create

That is, as shown in the diagram of FIG. 3A, when both selection signals Sel1 and Del2 are H, when the first pilot signal f1 and both selection signals Sel1 and Del2 are L and H, If the second pilot signal f2 and the two selection signals Sel1 and Del2 are L and H, the third pilot signal f3 and the two selection signals Sel1 and Del2 are both L, the fourth pilot signal f4. As shown in (b) of FIG. 3, the select signals Sel1 and Del2 are output as L and H according to the period of the head switching pulse SW to generate a recording pilot signal. .

The recording pilot signal of the square wave generated by the frequency divider 12 becomes the sine wave recording pilot signal while passing through the low pass filter 14.

The microprocessor 10 outputs both a tape type signal (ME / MP) and a recording speed signal (LP / SP) to L at the microprocessor 10 at the recording speed of the MP tape and the SP. Since L through (15) is inverted by inverter 16 and is input to the inverting input terminal of amplifier 17 by H, the sine wave recording pilot signal input to the non-inverting input terminal of amplifier 17 is 1 + R2 / R1. The gain is amplified and mixed in mixer 18 and recorded on 8 mm tape.

The microprocessor outputs one of the tape type signal (ME / MP) or the recording speed signal (LP / SP) to H when the tape speed is ME tape or LP. Since the inverter 16 is inverted to L and grounds the resistors R1 and R3, the sine wave recording pilot signal input to the non-inverting input terminal of the amplifier 17 is 1 + R2 (R1 + R3) / R1. The gain of R3 is amplified and recorded as a leveled recording pilot signal.

On the other hand, when playing an 8 mm tape, the signal picked up by the video head 2 is amplified by the preamplifier 3 and the envelope waveform is detected by the envelope detector 4.

The envelope detection waveform from the envelope detection unit 4 passes only 200 KHz or less in the low pass filter 5.

The low pass filter (5) uses 200 KHz because four pilot signals f1 to f4 are in the range of 102.54 to 165.21 (KHz).

The pilot signal detected by the low pass filter 5 is input to the balance modulator 7 to obtain a difference from the four reference pilot signals f1 to f4 input from the reference pilot signal generator 6.

This means that when the video head 2 traces the f1 track, the left and right sides of the video head 2 include the signals of the f4 and f2 tracks. If the f1 track is the reference pilot signal, the difference from the f4 track is 3fH ( 46 KHz), and the difference from the f2 track is 1 fH (16 KHz), so in the balance modulator 7, the difference between the left and right sides of the track currently being tracked, 16KHz and 46KHz, is the 16KHz bandpass filter (8a) and 46KHz bandpass, respectively. After passing through the filter 8b, DC detectors 8c and 8d detect DC levels, respectively.

16KHz and 46KHz through the detector 8 are compared with each other in the comparator 9 to detect the current tracing state, so that if there are 16KHz components, + 16KHz is positively output, and if there are many 46KHz components, -46KHz is A reproducing ATF error signal as shown in FIG. 1, output as a negative (-), is input to the microprocessor 10.

Therefore, the microprocessor 10 controls the capstan drive system 19 with reference to the reproduction ATF error signal to adjust the running of the 8 mm tape.

Therefore, the 8mm tape ATF compensation circuit reduces the level of the playback ATF error signal depending on the type of tape (ME or MP) and the recording speed (SP or LP). When the recording speed is LP, the microprocessor recognizes the tape type signal or the recording speed signal as H so that the recording pilot signal compensated and amplified by the amplifier is recorded on the 8mm tape along with the Y / C signal. The error signal can be detected stably.

Claims (2)

When the tape type signal (ME / MP) is input from the microprocessor in the deck that recognizes the type of inserted 8mm tape, the pulse input from the oscillator by the select signal (Sel1) (Sel2) from the received microprocessor In the ATF compensation circuit of 8mm tape which inputs four recording pilot signals f1 to (f4) which are divided by, and recognizes a signal in the playback ATF of 8mm tape during playback, the recording pilot signal from the divider. A low pass filter for converting the signal into a sine wave recording pilot signal, an orifice for logically combining the tape type signal (ME / MP) and the recording speed signal (SP / LP) from the microprocessor, the low pass filter and An 8mm tape ATF compensation circuit comprising amplifiers for receiving a signal through an inverter and selectively amplifying a recording pilot signal. The amplifier of claim 1, wherein the amplifier outputs one of the tape type signal (ME / MP) or the recording speed signal (LP / SP) from the microprocessor as H, and the gain = 1 + R (R1 + R3). 8mm tape ATF compensator for outputting pilot signals leveled down to size / R1 / R3.