Foreground subject-identifying apparatus
First Claim
1. A foreground subject-identifying apparatus which comprises a first signal-generating means for producing a first signal having a plurality of frequencies falling within a prescribed range;
- second signal-generating means for sending forth a second signal having a higher frequency than the first signal;
first frequency mixing means for mixing output signals from the first and second signal-generating means and modulating the second signal by the first signal to produce a modulated signal;
first transmission and reception means for transmitting an output signal from the first frequency mixing means;
second transmission and reception means for receiving a signal sent forth from the first transmission and reception means;
coding means provided with at least one resonance circuit to generate a coded signal corresponding to the frequency of said resonance circuit;
a nonlinear circuit provided with a nonlinear element, coupled between the second transmission and reception means and coding means, and adapted to detect a signal issued from the second transmission and reception means to supply the coding means with a signal corresponding to the first signal, and modulate a signal corresponding to the second signal by a coded signal from the coding means to deliver a modulated signal to the second transmission and reception means;
second frequency-mixing means for mixing an output signal from the second signal-generating means with a signal emitted from the second transmission and reception means and received through the first transmission and reception means;
a third frequency-mixing means for mixing a first signal produced from the first signal generating means and an output signal from the second frequency-mixing means, thereby generating a signal corresponding to the coded signal; and
a coded signal-interpreting circuit for judging the coded signal from an output signal of the third frequency-mixing means.
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Accused Products
Abstract
A foreground subject-identifying apparatus comprises a sweep signal generator for issuing a sweep signal having frequencies fs falling within a prescribed range; a carrier wave generator for producing a carrier wave having a frequency f0 ; a first frequency mixer for mixing output signals from the sweep signal generator and carrier wave generator to generate an output signal having a frequency f0 ±fs ; a first antenna through which to transmit an output signal from the first frequency mixer; a second antenna mounted on the foreground subject to receive an output signal sent forth from the first antenna; a coding circuit carried on the foreground subject which is provided with a plurality of resonance circuits resonating at different frequencies fT and adapted to form a specified code from a combination of these different resonance frequencies; a signal mixer for detecting an output signal from the second antenna to supply a signal having frequencies fs to the coding circuit and modulating the signal having a frequency f0 by resonance signals from the coding circuit to deliver a signal having a frequency f0 ±fT to the second antenna; a second frequency mixer for mixing an output signal having a frequency f0 from the carrier wave generator, and a signal having a frequency f0 ± fT received from the signal mixer through the second and first antennas and thereby issuing a signal having a frequency fT ; and a coded signal interpreting circuit for detecting resonance frequencies out of a signal delivered from the second frequency mixer, thereby interpreting a coded signal supplied from the coding circuit.
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Citations
13 Claims
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1. A foreground subject-identifying apparatus which comprises a first signal-generating means for producing a first signal having a plurality of frequencies falling within a prescribed range;
- second signal-generating means for sending forth a second signal having a higher frequency than the first signal;
first frequency mixing means for mixing output signals from the first and second signal-generating means and modulating the second signal by the first signal to produce a modulated signal;
first transmission and reception means for transmitting an output signal from the first frequency mixing means;
second transmission and reception means for receiving a signal sent forth from the first transmission and reception means;
coding means provided with at least one resonance circuit to generate a coded signal corresponding to the frequency of said resonance circuit;
a nonlinear circuit provided with a nonlinear element, coupled between the second transmission and reception means and coding means, and adapted to detect a signal issued from the second transmission and reception means to supply the coding means with a signal corresponding to the first signal, and modulate a signal corresponding to the second signal by a coded signal from the coding means to deliver a modulated signal to the second transmission and reception means;
second frequency-mixing means for mixing an output signal from the second signal-generating means with a signal emitted from the second transmission and reception means and received through the first transmission and reception means;
a third frequency-mixing means for mixing a first signal produced from the first signal generating means and an output signal from the second frequency-mixing means, thereby generating a signal corresponding to the coded signal; and
a coded signal-interpreting circuit for judging the coded signal from an output signal of the third frequency-mixing means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- second signal-generating means for sending forth a second signal having a higher frequency than the first signal;
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13. A foreground subject-identifying apparatus which comprises a first signal-generating means for producing a first signal having a plurality of frequencies falling within a prescribed range;
- second signal-generating means for sending forth a second signal having a higher frequency than the first signal;
first frequency mixing means for mixing output signals from the first and second signal-generating means and modulating the second signal by the first signal to produce a modulated signal;
first transmission and reception means for transmitting an output signal from the first frequency mixing means;
second transmission and reception means for receiving a signal sent forth from the first transmission and reception means;
coding means provided with at least one resonance circuit to generate a coded signal corresponding to the frequency of said resonance circuit;
a nonlinear circuit provided with a nonlinear element, coupled between the second transmission and reception means and coding means, and adapted to detect a signal issued from the second transmission and reception means to supply the coding means with a signal corresponding to the first signal, and modulate a signal corresponding to the second signal by a coded signal from the coding means to deliver a modulated signal to the second transmission and reception means;
first dividing means for dividing a signal received through the first transmission and reception means into two portions;
second dividing means for dividing an output signal from the second signal generating means into two portions having a phase difference of (n+1/2)π
(n is a positive integer);
second frequency mixing means having first and second frequency mixers connected to receive at one input terminal respective output signals of the first dividing means and to receive at the other input terminal respective output signals of the second dividing means, thereby respectively producing output signals corresponding to the frequency of an output signal from the coded means;
third frequency- mixing means having third and fourth frequency mixers connected to receive at one input terminal respective output signals from the first and second frequency mixers and to receive an output signal from the first signal generating means at the other input terminal first and second squaring means for squaring output signals from the third and fourth frequency mixers, respectively;
an adder for adding together output signals from the first and second squaring means to generate a signal corresponding to the coded signal; and
a coded signal-interpretting circuit for judging the coded signal from an output signal of the second frequency mixing means.
- second signal-generating means for sending forth a second signal having a higher frequency than the first signal;
Specification