Transceiver circuit for modulated infrared signals
First Claim
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1. A circuit, including a power supply, for detecting modulated infrared (IR) radiation of a predetermined modulation frequency while rejecting other IR emissions comprising:
- (a) at least one means for detecting IR radiation,(b) demodulation means operatively connected to said detecting means and tuned to said predetermined modulation frequency for producing an output signal when IR radiation at said predetermined modulation frequency is detected,(c) means for maintaining the sensitivity of the detecting means to the modulated IR signal of interest even in the presence of substantial background IR radiation includes a tank circuit interposed between said power supply and the detecting means, said tank circuit being tuned to produce a high impedance at said predetermined modulation frequency and a low impedance otherwise,whereby saturation of the detecting means by said background IR radiation is substantially prevented.
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Abstract
An infrared transceiver circuit for a toy gun or other novelty item includes an IR detector, a high Q band pass filter and a demodulator in the receiver section to control the operation of a counter which, in turn, actuates lights and sounds when a "hit" is detected. The transmitter portion generates an IR signal modulated by an oscillator and square wave generator. The high Q band pass circuit substantially eliminates unmodulated infrared as, for example, from sunlight, to increase receiver sensitivity.
56 Citations
14 Claims
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1. A circuit, including a power supply, for detecting modulated infrared (IR) radiation of a predetermined modulation frequency while rejecting other IR emissions comprising:
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(a) at least one means for detecting IR radiation, (b) demodulation means operatively connected to said detecting means and tuned to said predetermined modulation frequency for producing an output signal when IR radiation at said predetermined modulation frequency is detected, (c) means for maintaining the sensitivity of the detecting means to the modulated IR signal of interest even in the presence of substantial background IR radiation includes a tank circuit interposed between said power supply and the detecting means, said tank circuit being tuned to produce a high impedance at said predetermined modulation frequency and a low impedance otherwise, whereby saturation of the detecting means by said background IR radiation is substantially prevented. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A transceiver circuit, including a power supply, for transmitting to and detecting from other such circuits modulated infrared (IR) radiation of a predetermined modulation frequency comprising:
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(a) at least one means for detecting IR radiation, (b) demodulation means operatively connected to said detecting means and tuned to said predetermined modulation fequency for producing an output signal when IR radiation at said predetermined modulation frequency is detected, (c) means for maintaining the sensitivity of the detecting means to the modulated IR signal of interest even in the presence of substantial background IR radiation, said means for maintaining including a tank circuit interposed between said power supply and the detecting means, said tank circuit being tuned to produce a high impedance at said predetermined modulation frequency and a lower impedance otherwise, whereby saturation of the detecting means by said background IR is substantially prevented, (d) means for transmitting modulated IR radiation of said predetermined frequency, (e) means for inhibiting said transmitting means for a selected time period when said demodulator means produces said output signal, whereby two or more of said circuits can be employed in spaced relation and each can detect the transmissions of the other circuits but not of its own transmitting means. - View Dependent Claims (14)
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Specification