Intermusic detecting circuit for automatic music selecting device
AssigneePioneer Electronic Corporation
InventorShinya Takahashi
Life of this patent
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Abstract
An intersong detecting circuit for an automatic music selecting device for a record player in which intersong intervals are accurately detected even for a disc having irregular reflectivities or between discs of different reflectivities. An intersong sensor detects intersong intervals between adjacent songs on a recording disc. The output signal from the intersong sensor is sampled and held at a rate determined by a leading-in time/reproducing time time-constant switching signal. The sampled-and-held signal is compared with the output of the sensor to produce a differential signal and an intersong identification signal is produced when the differential signal exceeds a predetermined threshold value.
Claims6
An intersong detecting circuit for an automatic music selecting device comprising:
- an intersong sensor for detecting intersong intervals between adjacent songs on a recording disc;
- means for sampling an output signal from said intersong sensor at a predetermined rate and holding the sampled signal;
- means responsive to the held signal from said sampling and holding means and to said output from said sensor for comparing said held signal with said output from said sensor to thereby produce a differential signal;
- means responsive to the differential signal from said comparing means for producing an intersong identification signal when said differential signal exceeds a predetermined threshold value;
- and
- means for switching said sampling rate of said sampling and holding means between leading-in times and reproducing times of said recording disc.
An intersong detecting circuit for an automatic music selecting device comprising:
- a light emitting diode, light from said light emitting diode being directed onto a surface of a recording disc;
- a phototransistor having a light input disposed to receive light reflected from said recording disc;
- a buffer amplifier having an input coupled to an output of said phototransistor;
- a variable frequency clock generator having a control input coupled to receive a leading-in time/reproducing time time-constant switching signal, an output frequency of said clock generator being determined in accordance with a state of said leading-in time/reproducing time time-constant switching signal;
- a capacitor having a first terminal coupled to ground;
- an FET transistor having a first of a source and drain coupled to a second terminal of said capacitor and the other of said source and drain coupled to an output of said buffer amplifier and a gate coupled to an output of said clock generator;
- a second buffer amplifier having an input coupled to said second terminal of said capacitor;
- a differential amplifier having a non-inverting input coupled to said output of said first buffer amplifier and an inverting input coupled to an output of said second buffer amplifier;
- and a comparator having a non-inverting input coupled to an output of said differential amplifier and an inverting input coupled to a source of a predetermined reference voltage.
Dependencies are inferred from the claim text.