JPS5923229Y2 - Tape recorder track interval detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for detecting desired positions such as between tracks on a magnetic tape in a tape recorder.

Figure 1 shows a conventional device of this kind, where 1 is a magnetic tape;
2 is a recording head, 3 is an amplifier, 4 is a low frequency oscillator with a constant frequency, 5 is a playback head, 6 is an amplifier, 7 is a band pass filter, 8 is a detection smoothing circuit, 9 is a voltage level detection circuit, 1o is a mechanism drive Department.

The low frequency oscillator 4 amplifies its constant frequency output with an amplifier 3 and applies it to the recording head 2 to detect the position on the magnetic tape 1, which is generally a blank space between musical pieces. This is to record the location in advance.

To detect the song interval, the playback head 5 is moved to the magnetic tape 1.
I put the tape recorder in fast forward mode while it is in pressure contact with the
The prerecorded detection signal of the low frequency oscillator 4 is reproduced from the reproducing head 5 with a higher frequency corresponding to the faster running speed of the magnetic tape 1 than at the time of recording.

This reproduced output is amplified by an amplifier 6, and further, frequency components of the music signal and audio signal other than the frequency component of the detection signal are removed by a bandpass filter 7, and only the detection signal is added to the detection smoothing circuit 8.

When the signal of the detection signal frequency component continues for a certain period of time or more in the output of the reproducing head and the DC voltage level of the detection smoothing circuit 8 increases, the voltage level detection circuit 9 and the mechanism drive unit 1
The tape recorder is operated to stop the tape recorder at a desired position on the magnetic tape 1 or to switch the tape recorder to the playback state.

As mentioned above, in the conventional device, the frequency of the detection signal recorded on the magnetic tape is constant, and therefore, when fast forwarding, the detection signal reproduced increases in proportion to the faster running speed of the magnetic tape. Since the frequency also changes to higher levels, it is necessary to set a wide bandpass filter to pass only the frequency components of the detected signal, and the similar frequency of the external signal is the same. The disadvantage is that it is easy to malfunction.

The present invention attempts to eliminate the above-mentioned drawbacks of the conventional ones.

For this reason, the present invention uses, as a detection signal, the output of an oscillator whose oscillation frequency is proportional to the number of revolutions of the take-up reel of the magnetic tape being recorded, thereby creating a band-pass filter for selecting the detection signal. This narrows the band and reduces malfunctions.

FIG. 2 shows an embodiment of the present invention, in which 1 to 3.5 to 10 are the same as in FIG. 1, and 11 rotates in conjunction with the take-up reel shaft (not shown) of a tape recorder. A ring magnet, 12 is a Hall IC 112a attached adjacent to the ring magnet 11, and a Hall element whose resistance value changes with the rotation of the ring magnet 11, 12b
is an amplification section for extracting changes in the Hall element 12a as a signal.

In the above embodiment, while the magnetic tape 1 is running at a constant speed, the number of revolutions of the take-up reel is inversely proportional to the take-up diameter of the magnetic tape 1. When the winding diameter is small, the rotation speed of the ring magnet 11 that is linked to the take-up reel is high, and the frequency of the output signal of the Hall IC 12 is high. The rotation speed will be lower.

This is illustrated in Figure 3a.

Therefore, the frequency of the output signal of the Hall IC 12 recorded on the magnetic tape 1 changes as shown in FIG.

When the magnetic tape 1 is run in fast forward mode, the take-up reel is driven at a constant rotation speed by a motor (not shown).
The running speed of the magnetic tape 1 is proportional to the winding diameter, and increases with time as shown in FIG. 3C.

Therefore, the frequency of the detection signal reproduced from the reproducing head 5 during fast forwarding becomes approximately constant, as shown in FIG. 3d.

Therefore, the bandpass filter 7 for selecting the detection signal can have a narrow band, and therefore,
There are also fewer malfunctions.

Note that the detection signal of the present invention may be a signal obtained by intermittent light shielding between a light emitting element and a light receiving element by a rotating disk that works with a take-up reel, or a signal obtained by intermittently blocking light between a light emitting element and a light receiving element. It is also possible to use the output of a low frequency oscillator to obtain a signal for detection.

As described above, according to the present invention, the frequency of the inter-track detection signal played during fast-forwarding is approximately constant, and the band of the bandpass filter that selects this can be narrowed, which reduces malfunctions. A tape recorder inter-track detection method is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional tape recorder inter-track detection method, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is an explanatory diagram showing frequency changes of the detection signal. 1...Magnetic tape, 2...Recording head, 5...Playback head, 7...Band pass filter, 11...Ring magnet, 12...Hole ■C0

Claims (1)

[Scope of utility model registration request] In a track interval detection device for a tape recorder, a playback head is pressed against a magnetic tape to perform fast forwarding, a prerecorded detection signal is reproduced, and the signal is passed through a band pass filter as a signal for switching from a fast forwarding state to a stop or playback state.
A track interval detection device for a tape recorder, characterized in that the frequency of a detection signal for recording errors is proportional to the number of revolutions of a take-up reel.