JPS59172102A - Automatically tuning method of cassette tape recorder equipped with auto-reverse mechanism - Google Patents

Abstract

PURPOSE:To shorten the time required for automatic tuning by performing the automatic tuning while rewinding a magnetic tape and reproducing a test signal run on REW and recorded on the magnetic tape after recording the test signals for tuning on the magnetic tape while running the magnetic tape on FWD. CONSTITUTION:Since the Q-output of an FF20 goes to high when the running direction of a magnetic tape is reversed and, at the same time, tuning is started by switching the mode from recording to reproducing, the output of an EX-OR21 does not go to high even when a signal RV attains to high and a relay 25 does not make switching of an amplifier system. Therefore, change-over switches 7 and 8 remain at the (a)-side. Moreover, since the output of another EX-OR23 remains at low level even when a reverse signal R goes to high level, a recording-reproducing head does not move. When tuning is performed by reproducing signals for test immediately without rewinding the magnetic tape, the time required for making tuning can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an auto-tuning method for automatically setting the recording bias amount, equalizer characteristics, recording level, etc. according to the type of magnetic tape in a precoder.

The auto-tuning method for a tape recorder equipped with a conventional auto-reverse mechanism, particularly a tape recorder that performs recording and playback using a single recording/playback RAD, is, for example, as shown in Fig. 1. While the tape 1 is running in the forward (FWD) direction, the frequency and recording bias are determined by the recording/reproducing RAD 2 provided between the forward erase end 3 and the reverse erase end 4.

A tuning test signal in which the equalizer characteristics and the recording level are changed stepwise is recorded in the direction of arrow S to e, and then the magnetic tape 1 is rewound and the magnetic tape 1 is run in the forward direction again. , while playing back the test signal recorded there in the direction of arrow S to e.
Auto-tuning was performed by setting the optimal recording bias, equalizer characteristics, and recording level.

Therefore, since time is required to rewind the magnetic tape between recording and reproducing the test signal, there is a problem in that tuning takes time.

The present invention was made to solve the above problem, and an object of the present invention is to shorten the auto-tuning time in a cassette tape recorder equipped with an auto-reverse mechanism.

Therefore, the auto-tuning method according to the present invention
After recording a tuning test signal while running the magnetic tape in the forward (FWD) direction, run the magnetic tape in the reverse (REW) direction and perform auto-tuning while playing back the recorded test signal. This is what I decided to do.

In the normal operation of a tape recorder equipped with an auto-reverse mechanism, when the end of the magnetic tape is detected during recording or playback and the running direction of the magnetic tape is reversed, the recording/playback head is moved up and down and at the same time, in the case of stereo recording and playback, the recording/playback head is moved up and down. In order to do this, the recording and playback channels of the upper to rad sections and the lower head section were switched, or in the case of a rotary recording and playback head, the recording and playback tracks were switched by rotating the recording and playback head.

However, when performing auto-tuning according to the present invention, the tuning test signal is recorded while the magnetic tape is running in the forward direction, and then the running direction of the magnetic tape is reversed. The same track is played in the opposite direction without changing the playback channels or rotating the recording/playback mode, and auto-tuning is performed using the tuning signal recorded there.

For example, FIG. 2 (AXB) shows the configuration of the forward/reverse switching section of the playback system and recording system when performing back-and-forth stereo recording and playback with four tracks using a vertically movable two-channel recording/playback head. The upper head part and the lower head part of Re-RAD 2, 5 and 6 in the figure (A) are reproduction amplifiers, 7 and 8 are changeover switches, 9 is an L channel line output terminal, and 10 is an R channel line output terminal. In the figure (B), 11 is the line input terminal of the L channel, 12 is the line input terminal of the R channel, 1
3.14 is a recording amplifier, and 15.16 is a changeover switch.

In normal forward mode, selector switch 7.
Switches 8 and 15 and 16 are respectively switched to the A side and the C side, and the upper head section is in charge of L channel recording and the lower head section is in charge of R channel recording and playback, respectively. In the reverse mode, the selector switch 7.8 is switched to the b side and the selector switch 15.16 is switched to the d side, so that the upper head section 2a records the R channel, and the lower to rad sections 2b record the L channel. -Each person is in charge of playback.

In forward mode, the recording/playback RAD2 is in the lower R position, and the lower two tracks (A
In reverse mode, the recording/playback head 2 moves to the raised position and plays the upper 2nd side of the cassette tape.
Record and play back the trunk of the book (side B).

However, when performing auto-tuning according to the present invention, the test signal recorded in the forward mode is played back in the reverse mode, so in the reverse playback state during tuning, only the running direction of the magnetic tape is reversed, and the changeover switch 7° is turned off. 8 remains on side a, and does not move from recording/playback to rad.

In this way, the tuning time can be shortened by immediately reproducing the test 4- signal and performing tuning without rewinding.

Next, an example of a circuit for performing selection operations in the reverse mode during normal operation and during tuning will be explained with reference to FIG.

20 is a flip-flop circuit (FF) which inputs a tuning start signal TS and a tuning end signal TE from a tuning circuit (not shown); when the tuning start signal TS becomes HII, the Q output is set to "H", and the tuning end signal TB is set to "H". When Hn is reached, the Q output is set to "L11".

21, 22, and 23 are all exclusive OR circuits (E
The EX-OR 21 uses an amplifier system forward/reverse switching signal RV (which becomes H11 during !J parsing) from a system controller (not shown) as the other input signal.

The EX-ORs 22 and 23 respectively use a forward signal F and a reverse signal R, which are mechanical forward/reverse switching signals from the system controller, as other input signals.

Then, the output of this EX-OR21 is used as the transistor 24.
on and off to control the amplifier system switching relay 25,
When this relay is activated, the selector switch 7.8 in FIG. 2 is switched to the b side, and i5, 16 are switched to the d side.

Further, the recording/reproducing head driving means (not shown) is controlled by the outputs of the EX-ORs 22 and 23, and the recording/reproducing head 2 in FIG. 2 is brought to the lower position when the output of the EX-OR 22 is "H". When the output of EX-OR, 23 is "H", set it to the - light position.

Therefore, when switching from forward mode to reverse mode during normal recording/playback, the output of FF20 is set to II L, so when the signal R from the system controller becomes H, the output of EX-OR21 is becomes II HII and turns on the transistor 24, so the relay 25 operates and the selector switch 7 in FIG.
．． 8 to the b side and 15°16 to the d side.

At the same time, when the forward signal 1.゛ becomes L 11 and the reverse signal R becomes ``H'', the output of EX-OR 22 becomes ゛L'' and the output of 23 becomes t+HII, so the recording/reproducing head Raise 2.

However, when you switch from recording to playback and start tuning at the same time as reversing the running direction of the magnetic tape,
Since the Q output of FF 20 becomes "H", even if the signal RV becomes "H", the output of EX-OR, 21 does not become "H", and the transistor 24 is not turned on, so the relay 25 does not operate, and the amplifier System switching is not performed.

Also, even if the forward signal F becomes "L II" and the reverse signal R becomes "'H", the output of EX-OR, 22 remains "H", and the output of EX-OR2 becomes "II L". Since the position remains unchanged, the recording/reproducing head will not be moved.

In this way, when performing tuning while performing reverse playback, it is possible to erase the tuning test signal by passing an erasing current through the forward erasing head 6 shown in FIG. 1.

The method of setting the recording bias amount by tuning, equalizer characteristics, recording level, etc. is the same as the conventional method, and therefore a description thereof will be omitted.

As explained above, if the auto-tuning method according to the present invention is adopted, in a cassette tape recorder equipped with an auto-reverse mechanism, there is no need to rewind the magnetic tape between recording and playback of the tuning test signal. , auto-tuning time can be shortened.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the conventional auto-tuning method in a cassette tape recorder equipped with an auto-reverse mechanism. Fig. 2 (AXB) shows playback when reciprocating stereo recording and playback is performed using a vertically movable two-channel recording/playback head. FIG. 3 is a circuit diagram showing the configuration of the forward/reverse switching section of the system and the recording system. It is a diagram. 1... Magnetic tape 2... Recording/reproducing head 6.
4... Erasing head 5, 6... Playback amplifier 7
, 8.15.16... changeover switch 13, 14...
Recording amplifier 20...Flip-flop circuit (FF) 21-26.
...Exclusive OR circuit 25...Relay Fig. 1 Fig. 2 Fig. 3 +V R

Claims (1)

[Claims] 1. In a cassette tape recorder equipped with an auto-reverse mechanism, the magnetic tape is run in the forward direction while a tuning test signal is recorded, and then the magnetic tape is run in the reverse direction and the above-mentioned test signal recorded An auto-tuning method characterized by performing auto-tuning while reproducing signals.