JPS629529Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a tape recorder having an editor function for creating unrecorded portions during sound, and particularly relates to a tape recorder that can further reduce tape noise in unrecorded portions.

Some tape recorders have an editor function that actively creates unrecorded portions during recording. This unrecorded portion is necessary when performing song interval detection, and must be erased to the extent that tape noise can be ignored in order to prevent erroneous operation of song interval detection. In this case, erasing of the magnetic tape includes alternating current erasing and direct current erasing. AC cancellation has no power efficiency, but has good S/N,
Also, although DC cancellation has good power efficiency, the S/N ratio becomes low. Therefore, in large equipment that uses commercial power, AC erasure can be used to perform sufficient erasure, but in small tape recorders that use batteries as a power source, DC erasure must be used due to the power supply. .

FIG. 1 is a circuit diagram showing an example of a main part of a tape recorder having an editor function using direct current erasure, which has been commonly used in the past.
An erasing head 2 and a recording/reproducing head 3 driven by direct current are provided along the running path and spaced apart from each other by a predetermined distance in the running direction. During normal recording, this recording/playback head 3 amplifies the bias signal supplied from the bias oscillator 4 via the capacitor 5 and the input signal supplied to the input terminal 6, and amplifies the input signal supplied to the editor switch 7 and the resistor 8. The output signal of the recording amplifier 9 is supplied through the recording amplifier 9, and the audio signal is magnetically recorded on the magnetic tape 1 in an alternating current biased state. Next, when the editor switch 7 is opened during recording, the output of the recording amplifier 9 is cut off.
The recording/reproducing head 3 records only the bias signal, creating an unrecorded portion.

However, in the tape recorder having the editor function using DC cancellation described above, the residual noise in the unrecorded portion becomes large, so that the song interval detection circuit malfunctions due to this residual noise.

Therefore, an object of this invention is to provide a tape recorder having an editor function that can reduce residual noise in unrecorded portions to a negligible level while using direct current erasure with high power efficiency.

In order to achieve this purpose, this idea
This increases the alternating current bias current supplied to the recording head when creating unrecorded portions. The tape recorder according to this invention will be explained in detail below with reference to the drawings.

FIG. 2 is a circuit diagram showing an embodiment of the tape recorder according to this invention, and the same parts as in FIG. 1 are designated by the same symbols and detailed explanation thereof is omitted. In the figure, 10 is a capacitor having a sufficiently larger value than capacitor 5, and 11 is a switch that selectively supplies the output of bias oscillator 4 to capacitors 5 and 10, and this switch 11 is interlocked with editor switch 7. However, when the editor switch 7 is closed, the capacitor 5 is selected.

In the circuit constructed as described above, the editor switch 7 is closed during normal recording, and the switch 11 selects the capacitor 5 in conjunction with the editor switch 7. Therefore,
The output of the bias oscillator 4 is supplied to the recording/playback head 3 via a capacitor 5, and the output of the recording amplifier 9 is supplied to the recording/playback head 3 via an editor switch 7 and a resistor 8, thereby recording on the magnetic tape 1. . In this case, the AC bias current supplied to the recording/reproducing head 3 is set to an appropriate value by setting the value of the capacitor 5.

Next, when the editor switch 7 is opened to obtain an unrecorded portion, the switch 11 is switched to select the capacitor 10 in conjunction with the editor switch 7. When the editor switch 7 is opened, the output of the recording amplifier 9 to the recording/reproducing head 3 is cut off, resulting in a non-recording state. In this case, large residual noise remains on the magnetic tape 1 that has passed through the erasing head 2 driven by direct current. In response, the switch 11 is switched to the capacitor 10 side in conjunction with the editor switch 7. In this case, since the value of capacitor 10 is set to a sufficiently larger value than capacitor 5, the AC bias current supplied to recording/reproducing head 3 is increased. In this way, when the AC bias current is increased compared to that during normal recording, the residual noise remaining on the magnetic tape 1 supplied via the erasing head 2 becomes so small that it can be almost ignored.

In this way, by almost eliminating residual noise in unrecorded portions, the inter-music detection operation performed during playback becomes reliable, and the degree of freedom in designing the inter-musical detection circuit is improved.

In the above embodiment, the case where the invention is applied to a two-head type has been described, but the same effect can be obtained when the invention is applied to a three-head type. Also, in the above embodiment, the bias current variable circuit which increases the AC bias current in conjunction with the opening operation of the editor switch has been described in combination with a switch which selects capacitors of different values, but the invention is not limited to this, and it goes without saying that other configurations are also possible.

As explained above, in the tape recorder according to this invention, the AC bias current supplied to the recording head is increased when creating unrecorded sections compared to during normal recording, so the erasing head is driven by DC. When in use, it has the excellent effect of reducing residual noise in unrecorded areas to a negligible level.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a main part of an editor mechanism in a conventional tape recorder, and FIG. 2 is a circuit diagram showing a main part of an embodiment of a tape recorder according to this invention. 1...Magnetic tape, 2...Erasing head, 3...
Recording/playback head, 4...Bias oscillator, 5, 10...
...Capacitor, 7...Editor switch, 8...
...Resistor, 9...Recording amplifier, 11...Switch.

Claims (1)

[Scope of utility model registration request] In a tape recorder having a DC erasing head, a recording head, and an editor switch that cuts off the signal supply to the recording head in order to create an unrecorded part during recording, the unrecorded part is created in conjunction with the editor switch. A tape recorder equipped with a bias current variable circuit that increases the alternating current bias current supplied to the recording head compared to normal recording.