COMMUNICATION SYSTEM OF A CUE SIGNAL OR SIGNALS

• US 3,624,507 A
• Filed: 04/21/1967
• Issued: 11/30/1971
• Est. Priority Date: 04/21/1967
• Status: Expired due to Term

• Current Assignee: Masao Fukata, Shozo Takahashi
• Original Assignee: Masao Fukata, Shozo Takahashi
• Inventors: Fukata, Masao, Takahashi, Shozo
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US04/632,674
• Time in Patent Office: 1,684 Days
• Field of Search: 343/228,225,226,227 325/31,131,32,35,63,64,131,132,45,30 340/207,168,170,171
• US Class Current: 375/269
• CPC Class Codes: G04G 9/0005 Transmission of control signals
• CPC Class Codes: G08C 19/12 in which the signal transmitted is frequency or phase of ac
• CPC Class Codes: H04L 27/10 Frequency-modulated carrier systems, i.e. using frequency-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/103 Chirp modulation for spread spectrum techniques H04B1/69

Abstract

Disclosed herein is a system for transmitting a cue signal or signals by use of at least one wobbled wave obtained by slightly wobbling a low-frequency sinusoidal wave, in an intermittent periodic manner, along a substantially sawtooth wave pattern the number of cycles of which is determined in accordance with the cue signal to be transmitted: in which the transmitted wobbled wave is applied to a narrow passband filter and changed into a pulse train the number of pulses of which is equal to the number of cycles of the sawtooth wave pattern, wherein the pulses have a constant period irrespective of slight deviation of the wobbling frequency range and/or slight deviation of the center frequency of the narrow passband filter; and, in which the transmitted cue signal is detected by counting the number of pulses of the pulse train in consideration of the constant period of pulses.

Claims

1. A system for transmitting cue signals, comprising:

generator means for generating a wobbled wave by intermittently wobbling the frequency of a low-frequency sinusoidal wave in accordance with a substantially sawtooth wave pattern the number of cycles of which is determined in accordance with the cue signal to be transmitted;

modulator means connected to said generator means for modulating a carrier wave with said intermittent wobbled wave;

transmitter means connected to said modulator means for transmitting said modulated carrier wave into a transmission medium;

receiver means for receiving said modulated carrier wave from the transmission medium to detect the wobbled wave;

a filter means coupled to the receiver means and having a passband narrower than the wobbling frequency deviation of said wobbled wave for developing a pulse train whose pulse period is substantially the same as that of said intermittent wobbled wave and having a number of pulses corresponding to the number of cycles of said sawtooth pattern; and

detection means coupled to said filter means for detecting the cue signal from the periodic characteristic of the pulses of the pulse train.

2. A system as set forth in claim 1, in which the generator means comprises a sinusoidal wave oscillator for generating a sinusoidal wave, an intermittent sawtooth wave generator for generating intermittently and periodically cycles of a sawtooth wave, and wobbling means coupled with the sinusoidal wave oscillator and the intermittent sawtooth wave generator for wobbling the sinusoidal wave along the intermittent sawtooth wave to produce an intermittent wobbled wave.

3. A system as set forth in claim 2, in which the intermittent sawtooth wave generator comprises means for shifting the instantaneous frequency of the intermittent wobbled wave to the outside of the passband of said filter means.

4. A system as set forth in claim 1, in which the generator means comprises a sinusoidal wave oscillator, a sawtooth wave generator for generating a sawtooth wave and a gate signal synchronized with the sawtooth wave, wobbling means coupled to the sinusoidal wave oscillator and the sawtooth wave generator for wobbling the sinusoidal wave from the sinusoidal wave oscillator along the sawtooth wave generated from the sawtooth wave generator to produce the wobbled wave, and gating means connected to the wobbling means for synchronously gating the wobbled wave with said gating signal, thereby generating the intermittent wobbled wave.

5. A system as set forth in claim 1, in which the generator means comprises a sinusoidal wave oscillator, a sawtooth wave generator for generating a sawtooth and a gate signal synchronized with the sawtooth wave, gating means couPled to the sinusoidal wave oscillator and the sawtooth wave generator for gating a sinusoidal wave derived from the sinusoidal wave oscillator to produce a gated sinusoidal wave, and wobbling means coupled to the gating means and the sawtooth wave generator for wobbling the gated sinusoidal wave along the sawtooth wave, thereby generating the intermittent wobbled wave.