DE3010795A1 - CIRCUIT DEVICE FOR TAPE PLAYBACK DEVICES - Google Patents

Description

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Circuit device for tape playback devices

The invention relates to a circuit device for switching on the preference track automatically, the transport direction of the tape switching playback devices.

With conventional tape playback devices in which the tape can only be played in one transport direction, the belt always moves from left to right, i.e. H. in the direction of rotation of the preference track, e.g. track 1, on the other hand track 2 is recorded against the direction of rotation of the preference track.

If playback devices are equipped with automatic switchover of the transport direction of the tape, when the tape is ejected at the end of a played track, either the transport direction of the tape is retained or the switch Fs / ai to

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preset in the opposite direction. As a rule, the direction of rotation of the tape is retained when a cassette is attached track that has not been fully played is ejected.

The consequence of this situation is that in the event that the Switching device remains preset, playing a tape in the same previously set direction when inserting a new cassette. However, if the switching device is set to switch before, this will be The tape of the inserted cassette is played in the opposite direction.

In all cases it appears that the actual direction in which the tape is played is when the cassette is inserted is not determined in advance, so that in practice each time a cartridge is inserted, the user will not be able to select one to recognize certain transport direction of the tape and thus the playback of a certain track in advance.

The invention has for its object to provide measures to overcome these difficulties and the playback device to switch in such a way that when a new cassette is inserted, the tape is always in the transport direction of the preference track regardless of the direction in which the previously inserted tape was played.

According to the invention, this object is achieved in that detector devices monitor the direction of rotation of the tape when it is inserted respond to the tape cassette and provide a first output signal if the transport direction of the tape of the transport direction corresponds to the preference track, as well as a second

The end-

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Deliver Ausgarigssignal when the tape rotates against the direction of rotation of the preference track, and that switching devices are available to the transport direction of the tape in the direction of rotation as a function of the second output signal
to switch the preference lane.

Further embodiments of the invention are the subject of
further claims.

By the measures of the invention it is achieved in an advantageous manner that in playback devices with automatically switching transport directions of the tape, a newly inserted tape
The cassette is always played in the direction of the preference track.

The advantages and features of the invention also emerge from the following description of an exemplary embodiment in FIG Connection with the claims and the drawing. Show it:

Fig. 1 is a block diagram for switching on the

Preference track in playback mode;

Fig. 2 is a detailed circuit diagram after the block

diagram according to FIG. 1;

The block diagram according to FIG. 1 comprises a detector 1, with which the rotation of the tape winding plate 5 is detected, who carries the take-up spool. At the output of the detector 1, depending on whether the tape reel disc 5 is rotating or whether it is rotating rests, a logic signal 0 or 1 is present.

A monostable multivibrator 2 is from the output signal

of

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of the detector 1 is applied and delivers an output pulse, whenever there is a change from logic signal state 0 to logic signal state 1 at the detector output. This output pulse from the multivibrator is transmitted via a transistor 6 to a switching relay Rl, the excitation thereof falls off and reverses the transport direction of the belt «

The circuit also includes a switch S1, which is dependent operated from the cassette position and from an inoperative position is closed. In this way, the relay R1 and the motor 7 are energized.

Two further switches S2 and S3 are closed as a function on the position of a bistable element, which the transport direction of the tape either for playback of track 1 or for playing track 2.

Furthermore, the block circuit comprises a multivibrator 3, which via a capacitor 8 when the device is switched on logic signal level zero is switched back and only assumes logic signal level 1 when switch S2 is closed. In the closed state, Mas.se is applied to the multivibrator, which switches on the direction of rotation for playing track 1 is. An OR gate 4 supplies the logic signal level zero on the output side if, after the closing of the Switch Sl the switch S3 - for the direction of rotation for playing track 2 - is first closed and thus a Logical signal level zero denotes KrrejiimgsabfaU dos Holais Rl triggers via transistor 6. This will make the l'mkohn

the

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the transport direction of the tape triggered.

The block diagram shown in Fig. 1 can be realized by the detailed circuit shown in FIG the functional circuit blocks are each indicated with dashed lines and the same reference numerals.

In operation, the switch S1 is closed by inserting the cassette when it is in the operating position and thus the power supply to the relay Rl and the motor 7 is applied. The motor 7 starts to run and drives the Wrapping plate 5 accordingly. The logic signal level zero and an output of the is therefore at the output of the detector 1 Multivibrators 2 show the logical signal level 1. The excitation of the relay 1 is thus maintained via the transistor 6.

Two possible situations can occur in this switching state:

a) switch S3 is closed and switch S2 is open;

b) switch S3 is open and switch S2 is closed.

In case a) the direction of rotation for playing track 2 is either pre-set or is already pre-set. In the Situation b) the direction of rotation for playing track 1 is either preset or is preset.

For the case a) is at the output of the OR gate 4 that logical signal level zero, because of the open switch S2 and the resetting of the multivibrator 3 to the logical

Signal -

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Signal level zero after closing the switch across the capacitor 8, both inputs of the OR gate with the logical Signal level zero are applied. However, if the logic signal level is zero at the output of the OR gate 4, the falls Excitation of the relay Rl, so that the direction of movement of the tape is reversed. At this point the situation is b) given, so that the logic signal level 1 at the output of the multivibrator 3 and also at the output of the OR gate 4 the logical signal level 1 appears. As a result, the relay Rl is energized again, so that a transport of the tape in one direction takes place, which is the playback of track 1, d. H. corresponds to the desired direction of transport.

It follows that the transport direction for playing track 1 is always the first transport direction when inserting of a cassette is set even if the transport direction for playing track 2 is preset from the last use was.

After the multivibrator has changed to a state in which a logic signal level 1 is present at the output a subsequent actuation of the switches S2 and S3 no longer brings about such a change that would occur at the output of the OR gate would trigger a change in the signal level, which is now at logic signal level 1 lies and remains lying on this.

In the situation given above under b), the logic signal level 1 is at the output of OR gate 4, because one of the two inputs has the same signal level. Simultaneously

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switch S3 is opened early. Under these circumstances, the excitation of the relay Rl can not drop, so that a reversal the transport direction of the belt is omitted.

On the basis of this explained mode of operation, in which the circuit in situation b) reacts to a change in the switching state the switch S1 and S2 does not respond, the circuit is automatically brought into a state when situation b) is reached t, in which it can no longer respond to circuit changes.

The preset transport direction or the transport direction, which is set when the tape is inserted is therefore always the one that is assigned to the playback of track 1.

It should also be mentioned that after inserting a cassette, if both switches S2 and S3 remain open for a first time interval, there is no change in the operating state, since in this Phase at the output of the multivibrator 3 and thus the logic signal level zero is applied to the assigned input of the OR gate 4, whereas at the other input of this OR gate the logic signal level 1 is applied. This results in the exit of the OR gate the logic signal level 1, which in turn does not trigger a drop in excitation for the relay Rl.

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Claims (4)

Claims ¹ X. Switching device for switching on the preference track in playback devices which automatically switch the transport direction of the tape, characterized in that - That detector devices respond to the direction of rotation of the tape when inserting the tape cassette and a first Deliver output signal if the transport direction of the tape corresponds to the transport direction of the preference track, as well provide a second output signal when the tape rotates against the direction of rotation of the preference track, - and that TJ ms maintenance facilities are in place in order to be dependent to switch the transport direction of the tape into the direction of rotation of the preference track from the second output signal. 2. Circuit device according to claim 1, characterized in that - That the detector devices comprise two switches, one of which is open and the other depending on the Position of a bistable element is closed, the bistable element presetting the transport direction of the tape, and - - That the first switch is closed when the direction of rotation of the preference track is switched on, whereas the second switch is closed when the tape rotates against the direction of rotation of the preference track. 030039/0875 - 2 - SB12P-21Ü4 3. Circuit device according to claim 1 or 2, characterized marked inet, - That further shutdown devices are available to the To make switching device ineffective when a reversal of the transport direction has taken place. 4. Circuit device according to claim 3, characterized in that - that the reversing devices and the defeat devices include: - an OR gate that has an input connected to the second switch, -a bistable multivibrator whose output is connected to the second input of the OR gate and whose setting input is connected to the first switch, - A capacitor that has one connection at the reset input of the bistable multivibrator and with his other terminal is at the logical reference level zero, the OR gate and the bistable multivibrator in such a way are arranged that a logic signal level 1 appearing at the output of the OR gate is a reversal of the transport direction triggers due to the drop in excitation of the relay. 030039/0875