JPS604268Y2 - magnetic recording and playback device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a magnetic recording/playback device that can automatically locate the beginning of content recorded on a magnetic recording medium such as a magnetic tape using a plunger. The purpose is to prevent the noise that accompanies the operation from being reproduced when it operates.

In conventional magnetic recording and playback devices, the playback button and rewind button or fast forward button are pressed at the same time to run the magnetic tape, and in this state, the playback head detects unrecorded parts of the magnetic tape or specific signal recording parts, so-called gaps between songs. When the disc is played back, the plunger is operated using this detection output to unlock only the rewind button or the fast forward button, and automatic playback operation is performed, so-called cueing.

However, with this type of device, since the signal is being reproduced even during the inter-track detection operation, when the plunger operates, the magnetic flux is mixed into the reproduced signal transmission path as noise, making the user feel uncomfortable. will be given.

Therefore, the present invention aims to eliminate such conventional drawbacks, and one embodiment thereof will be described below with reference to the drawings.

In FIG. 1, 1 is a playback head, 2 is a playback amplifier, and 3 is a magnetic tape.

When the magnetic tape 3 is run at high speed with the playback button and rewind button or fast forward button pressed simultaneously and the playback head 1 and playback amplifier 2 are activated, the difference between adjacent recorded parts of the magnetic tape 3 When a so-called song interval (here, an unrecorded portion) is detected by the magnetic head 1, this detection output is supplied to a trigger generation circuit 4 through a reproduction amplifier 2, and this circuit 4 is operated.

This trigger generation circuit 4 responds to sudden changes in the input signal level (
This is a circuit that generates a negative trigger for the trigger (see A in FIG. 2).

When the negative trigger output from the trigger generation circuit 4 is applied to the base of the transistor 5, the transistor 5 changes from a conductive state to a non-conductive state.

(Figure 2A shows changes in the base voltage and collector potential of transistor 5.

) Then, the capacitor 7 is charged with the passage of time determined by the time constant of the resistor 6 and the capacitor 7, and the transistor 8
A voltage is applied to the base of transistor 8, and this transistor 8 changes from a non-conducting state to a conducting state.

(Figure 2 shows changes in the base potential and collector potential of transistor 8.

) As a result, the muting circuit 10 is activated via the diode 9 to cut the output (the second figure shows the reproduction output change).

), the silicon transistor 12 changes from a conductive state to a non-conductive state, and the transistor 13 changes from a non-conductive state to a conductive state via the germanium diode 11. shows the change in

) A driving current flows through the electromagnetic plunger 14.

By operating this plunger 14, the rewind button or the fast forward button is unlocked and the device automatically enters the playback state.

Next, when the trigger level returns to, for example, 0.6V, the second
As shown in the figure, transistor 5 changes from a non-conducting state to a conducting state, transistor 8 changes from a conducting state to a non-conducting state, and the collector potential rises to around the muting circuit power supply voltage B2.

Since this B2 is set higher than the power supply voltage B□ of the plunger drive circuit, etc., the diode 11 is reverse biased,
Transistor 12 changes from a non-conducting state to a conducting state, and transistor 13 changes from a conducting state to a non-conducting state.

As a result, the drive current of the electromagnetic plunger 14 ceases to flow, and at the same time, the operation of the muting circuit 10 is canceled.

The above operation is performed, and while the electromagnetic plunger 14 is operating, that is, during the conduction time shown in FIG. 2G, no reproduction output is produced as shown in the second diagram.

Note that the muting circuit 10 is connected to a reproduced signal transmission line 15.
is grounded to mute the reproduced signal.

16 is a reproduction output terminal.

As explained above, according to the magnetic recording/playback device of the present invention, since the playback output is muted while noise is generated due to the operation of the electromagnetic plunger, it is no longer possible to generate harsh noise. The quality of the device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a waveform diagram of each part thereof. 1... Playback head, 2... Playback amplifier, 3... Magnetic tape, 4... Trigger generation circuit, 10... Muting circuit, 14・
...Electromagnetic plunger.

Claims (1)

[Scope of utility model registration request] A track interval detection means for detecting a track interval on a magnetic recording medium, a plunger drive circuit operated by the detection output of the track interval detection means, a plunger driven by the plunger drive circuit to switch the operating state of the device, and a reproduction signal. The detection output of the inter-music detection means is applied as a control input to the muting circuit, and while the plunger drive circuit is operating according to the detection output of the inter-music detection means, A magnetic recording/playback device characterized in that it is configured to operate a muting circuit to mute a playback signal.