JPS6323766Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting inter-track portions of a record disc in a record playing device.

As shown in FIG. 1, a conventional record disc track interval detection device has a light emitting element 2 and a light receiving element 3 arranged opposite to a record disc 1, and irradiates the record disc 1 with light from the light emitting element 2. , the reflected light from the record 1 is received by the light receiving element 3, and the received light output is sent to the amplifier 4.
This received light output and reference voltage after amplification by
The comparator circuit 5 compares the output signal Es with the comparison circuit 5, and uses the comparison output as an inter-track detection signal.

In such a conventional configuration, the light emitting element 2,
Due to variations in the characteristics of the light-receiving element 3, temperature characteristics, etc., the light-receiving output (its DC level) changes as shown in Figure 2a. In addition to the light receiving output a, the light receiving output b generated by the small level signal part of the sound groove part 1b and dust is also included, so the value of the reference voltage Es is as shown in Fig. 3 b to d. Since the inter-track detection signal is different between the two, not only is it impossible to accurately detect the inter-track section 1a, but the reference voltage Es has to be adjusted and set individually.

The present invention improves on these conventional drawbacks, and will be explained below with reference to the drawings.

In FIG. 3, parts that are the same as those in the conventional example shown in FIG. 1 are given the same reference numerals, and their explanation will be omitted.

In Figure 3, the received light output (output of amplifier 4)
(dotted line B in FIG. 4a) is amplified by the band amplifier 5, and the received light output component corresponding to the inter-track portion 1a is amplified to obtain a signal as shown by the solid line A in FIG. 4a. This signal A and the above-mentioned light reception output B are compared by a comparator circuit 6, and a comparison output C as shown in FIG. 4b is taken out as a first song interval detection signal.

That is, by band-amplifying the received light output (dotted line B in FIG. 4a), the received light output component corresponding to the inter-track portion 1a is amplified, that is, the DC component of the received light output is The corresponding received light output component is amplified to obtain a signal as shown by the solid line A in FIG. 4a. Then, this received light output component and the above received light output are compared, in other words, subtracted, and the fourth
Only the shaded portion in Figure a (light reception output caused by small level signal portions and dust in the inter-track portion 1a and sound groove portion 1b) is detected, and this detection output is transferred to the first
The signal is extracted as the inter-track detection signal.

On the other hand, the signal recorded on the record disc 1 is taken out by the pickup 7, and amplified by the amplifier 8 to take out a signal D as shown in FIG. 4c. Thereafter, the rectifier circuit 9 obtains a signal E as shown in FIG. 4d, and the comparator circuit 10 compares this signal E with the reference voltage Es, resulting in a comparison output as shown in FIG. 4e. F is taken out as the second inter-track detection signal.

That is, the first and second inter-song detection signals C and F are both set so that the signal voltage changes from a high level to a low level in the inter-song section 1a.

and the first and second inter-song detection signals C,
F is input to a logic circuit, for example, a NOR circuit 11, to obtain an output as shown in FIG. Extract as

The above configuration uses the received light output B as a reference voltage, compares this reference voltage with the received light output component A corresponding to the song interval part 1a obtained by band-amplifying the received light output B, and uses the comparison output C as a reference voltage. The logical output of this first inter-track detection signal and the comparison output F corresponding to the inter-track section 1a of the record 1 detected by the pickup 7 is used as the inter-track detection signal. By band-amplifying the received light output (dotted line B in FIG. 4a) and enhancing the received light output component corresponding to the inter-track part 1a with respect to the DC component of the received light output, the inter-track part 1a It is possible to accurately extract the light reception output corresponding to , and therefore, the first inter-track detection signal is accurate, and the logic between this first inter-track detection signal and the second inter-track detection signal is Since the output is the inter-track detection signal, the detection accuracy of the inter-track section is significantly improved, and it is possible to detect variations in the characteristics of the light-emitting element 2 and the light-receiving element 3, the temperature characteristics, the small level signal part of the sound groove 1b of the record 1, etc. The inter-track portion 1a of the record 1 can be accurately detected without being affected by dust or the like.

As described above, in the present invention, the comparison output between the light receiving output B of the light receiving element 3 and the output obtained by amplifying the light receiving output component A corresponding to the song gap 1a of the record 1 is used as the first song gap detection signal. , the logical output of this first inter-track detection signal and the second inter-track detection signal detected from the recording signal of the record disc 1 is used as the inter-track detection signal, so that the track interval detection signal of the record disc 1 is This has the advantage that the gap 1a can be detected accurately.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional record disc track interval detection device, FIG. 2 is an explanatory diagram of the same, and FIG. 3 is a diagram showing the configuration of a record disc track interval detection device of the present invention. FIG. 4 is an explanatory diagram of the same. 1 is a record disc, 2 is a light emitting element, 3 is a light receiving element, and 7 is a pickup.

Claims (1)

[Scope of utility model registration request] A light-emitting element 2 and a light-receiving element 3 are arranged opposite to the record 1, the light from the light-emitting element 2 is irradiated to the record 1, and the light reflected from the record 1 is received by the light-receiving element 3. Then, the light reception output component corresponding to the song interval 1a of the light reception output is amplified by the band amplifier 5, and the comparison output between the amplified output and the light reception output is used as a first song interval detection signal. The logical output of the first song detection signal and the second song gap detection signal obtained by rectifying and waveform-shaping the recording signal of the record 1 detected by the pickup 7 is used as the song gap detection signal. A device for detecting the inter-track portion of a record disc.