JPH0115003Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a means for displaying the level of a signal recorded on a magnetic tape and a means for detecting a no-signal portion between signals such as music recorded on a magnetic tape. The present invention relates to a tape recorder having a function of controlling the running operation of a magnetic tape.

Recently, tape recorders equipped with a song selection function that allows you to quickly search for the location where a desired music signal is recorded by detecting the no-signal area between the signals have become popular. . Additionally, tape recorders are generally equipped with display means for displaying the level of the recording signal and the level of the playback signal, but there are tape recorders that display the level by lighting up a plurality of light emitting elements as the display means. Often seen.

The present invention is intended to provide a circuit suitable for a tape recorder that is equipped with a display means using a plurality of light emitting elements as described above and also has a music selection function, and will be described in detail below with reference to the illustrated embodiments. explain. Reference numeral 1 designates a display circuit for displaying the level of a recording signal or a reproduction signal, and includes an input terminal 2 into which a signal whose level is displayed is rectified and input. 3, 4, 5, 6 and 7 are comparators each having an input terminal to which the signal from the input terminal 2 is applied and a reference signal input terminal to which a reference voltage is applied, and the signals input to the input terminals are It is set to output an H (high) level signal to the output terminal when the level becomes higher than the reference voltage. 8
is a current setting resistor, 9 is a Zener diode for setting the reference voltage, 10, 11, 12, 13 and 1
4 is a resistor for applying different reference voltages to the reference signal input terminals of the comparators 3, 4, 5, 6, and 7. 15, 16, 17, 18 and 19
whose bases are respectively the comparator 3,
4, 5, 6 and 7, each collector is connected to a power supply, and each emitter is a light emitting diode 20, 21, 22, which is a light emitting element.
23 and 24 are connected as loads. 25
2 is a no-signal detection circuit that detects a no-signal area between signals recorded on a magnetic tape, and the song selection switch 26 is closed when a song is selected, and is kept in the song selection operation state when it is in the suction operation state. A plunger 27 that switches the tape recorder to a playback state upon returning to a non-suction state, a plunger driving transistor 28 that causes the plunger 27 to be driven by suction, and a plunger driving transistor 2
a resistor 29 that supplies a bias current to the base of 8;
It is composed of 30 etc. Further, a connection point A between the resistors 29 and 30 is connected to the emitter of the driving transistor 15 constituting the display circuit 1 via a capacitor 31 and a resistor 32.

The present invention is constructed as described above, and its operation will be explained next. When a regeneration operation is performed, the drive mechanism enters a constant speed drive state for regeneration, and power is supplied to the amplifier circuit and the like to enter a regeneration state. The signals recorded on the magnetic tape are reproduced by a magnetic head, emitted by a speaker, etc., and then rectified by a rectifier circuit (not shown) and then applied to the input terminal 2 of the display circuit 1 . Ru. As the level of the signal applied to the input terminal 2 increases, the level of the output signals of the comparators 3, 4, . . . becomes H level in that order. As a result, an H level signal is applied to the base of the driving transistor 1.
5, 16... are sequentially inverted to conductive state, and the light emitting diodes 20, 21 connected as their loads
... are lit one after another. Therefore, the level of the reproduced signal is indicated by the number of light emitting diodes 20, 21, . . . , 24 lit. In this way, the level display operation is performed in the reproduction operation state, but the level display of the recording signal can also be performed in the same way. Also, in the playback mode, the song selection switch 2
6 is open, and the plunger 27 is in a non-suction operating state. Therefore, when a fast-forward or rewind operation is performed in a playback state in which the music selection switch 26 is open, the fast-forward or rewind operation button is not locked in the operating position, and the tape recorder cue or review operation is performed.

As described above, the level display operation and the like are performed in the playback operation state, but next, the music selection operation will be explained. Song selection switch 2 when in playback mode
When the plunger 6 is closed, the plunger driving transistor 28 becomes conductive, causing the plunger 27 to perform a suction operation. When the fast forward or rewind operation button is operated in such a state, the fast forward or rewind operation button is locked in the operating position by the suction action of the plunger 27, and the music selection operation state of the tape recorder is established. In this state of music selection operation, the magnetic head is in contact with the magnetic tape,
The signal reproduced by the magnetic head is input to input terminal 2.
will be applied to Since the playback signal is applied to input terminal 2 while the recorded signal is passing through, the output signal of comparator 3, which is set to the minimum level, becomes H level, and this signal is applied to the bass. The driving transistor 15 is in a conductive state. Fast forwarding or rewinding of the magnetic tape is performed in this state, but when the no-signal area between the signals comes to the position of the magnetic head, the signal applied to the input terminal 2 disappears. Comparator 3 output is lower than H level
Invert to (lower) level. The comparator 3
When the output becomes L level, the driving transistor 15 which was in a conductive state is reversed to a non-conductive state, and the potential of its emitter becomes L level. When the emitter potential of the driving transistor 15 becomes L level, the potential at the connection point A between the resistors 29 and 30 drops to the L level, and the plunger driving transistor 28, which was in a conductive state, is reversed to a non-conductive state. The plunger driving transistor 2
8 becomes non-conductive, the plunger 27 that was in the suction operation state is returned to the non-suction operation state, and as a result, the fast forward or rewind operation button is released from being locked in the operating position, and the tape recorder returns to the playback operation state. The desired song or the like will be played.

In this embodiment, the plunger is held in the suction operation state in the music selection state, and the music selection operation state is released by making the plunger into the non-suction operation state. It is also possible to configure the music selection operation state to be canceled when the music selection operation state is released. Moreover, although the switching operation of the plunger is used to switch from the song selection operation state to the playback state, it is also possible to switch to the stop state. Although a light emitting diode is used as a light emitting element for displaying a signal level, it is of course possible to use other light emitting elements, and the number thereof is not limited. Furthermore, although the signal for detecting the no-signal portion is obtained from the comparator set to the minimum level, it is also possible to obtain it from another comparator.

As explained above, the present invention not only can control the running operation of a magnetic tape by detecting the non-signal parts between the signals of music etc. recorded on the magnetic tape, but also detects the non-signal parts. Since the signal for detecting the signal level is obtained from the display circuit that displays the signal level, there is no need to provide a special amplifier circuit or the like for detecting the no-signal portion, and the circuit structure is advantageously simplified. Furthermore, since a signal for detecting a no-signal area is obtained from a plurality of comparators provided in the display circuit, the detection operation level for a no-signal area can be set arbitrarily, which increases the practicality of the present invention. It is very expensive.

[Brief explanation of the drawing]

The illustrated circuit is one embodiment of the present invention. Explanation of main drawing numbers, 1 ...display circuit, 3, 4,
5, 6, 7...Comparator, 15, 16, 1
7, 18, 19...driving transistor, 25
...No-signal portion detection circuit, 26...Music selection switch,
27...Plunger, 28...Plunger driving transistor.

Claims (1)

[Scope of utility model registration request] In a tape recorder that has a function of controlling the running operation of a magnetic tape by detecting a non-signal portion between signals recorded on the magnetic tape, the reference levels are different, and the difference between the reference level and the input signal is different. It includes a plurality of comparators that output a signal compared with the level, a plurality of light emitting elements that are driven to turn on by the output signal of each of the comparators, and a plunger that switches the running operation of the magnetic tape when no signal is detected. 1. A tape recorder circuit comprising a no-signal portion detection circuit, wherein a control signal for the detection circuit is obtained from the output of the comparator.