Wireless 900 MHz monitor system
First Claim
Patent Images
1. A low power communication device for transmitting and receiving frequency modulated radio signals in the 900 MHz band for monitoring an audio signal from a remote location, said device comprising:
- a transmitter unit having a housing defining a transmitter cavity therein and a pair of terminals directly connected to a power source having an unregulated predetermined DC output voltage;
a transducer mounted to said housing for converting the audio signal to an electric signal;
a transmitter circuit disposed in said transmitter cavity and connected to said pair of terminals, said circuit including,an amplifier component connected to said transducer for amplifying said electric signal; and
a frequency modulator component having a carrier frequency within the range of 900 to 928 MHz, said carrier frequency being modulated by said amplified electric signal for generating a modulated electric signal;
a transmitter antenna connected to said modulator for radiating said modulated electric signal;
a receiver unit having a housing defining a receiver cavity therein;
a receiver antenna mounted to said housing for receiving said radiated modulated electric signal;
a receiver circuit disposed in said receiver cavity, said receiver circuit including,a downconverter stage connected to said receiver antenna for converting said modulated electric signal to a second modulated signal having a frequency less than said carrier frequency, said second modulated signal containing frequency components representative of said electric signal generated by said transducer; and
a demodulator connected to said downconverter stage for demodulating said second modulated signal to obtain said electric signal; and
a speaker for converting said electric signal to said audio signal;
wherein said components of said transmitter circuit are driven by a voltage substantially equal to said unregulated predetermined DC output voltage so that one of a voltage regulator voltage step-up converter and voltage step-down converter is not required for transmitter circuit operation.
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Accused Products
Abstract
A communication device for monitoring audio signals transmitted st high frequencies from a remote location. The device includes a transmitter unit and a receiver unit containing a transmitter circuit and a receiver circuit, respectively. The transmitter and receiver circuits are designed for DC operation at voltages substantially equal to the DC voltages directly applied to the transmitter and receiver units so that the use of step-up converters can be avoided, thereby increasing the duration of time for DC power operation.
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Citations
25 Claims
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1. A low power communication device for transmitting and receiving frequency modulated radio signals in the 900 MHz band for monitoring an audio signal from a remote location, said device comprising:
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a transmitter unit having a housing defining a transmitter cavity therein and a pair of terminals directly connected to a power source having an unregulated predetermined DC output voltage; a transducer mounted to said housing for converting the audio signal to an electric signal; a transmitter circuit disposed in said transmitter cavity and connected to said pair of terminals, said circuit including, an amplifier component connected to said transducer for amplifying said electric signal; and a frequency modulator component having a carrier frequency within the range of 900 to 928 MHz, said carrier frequency being modulated by said amplified electric signal for generating a modulated electric signal; a transmitter antenna connected to said modulator for radiating said modulated electric signal; a receiver unit having a housing defining a receiver cavity therein; a receiver antenna mounted to said housing for receiving said radiated modulated electric signal; a receiver circuit disposed in said receiver cavity, said receiver circuit including, a downconverter stage connected to said receiver antenna for converting said modulated electric signal to a second modulated signal having a frequency less than said carrier frequency, said second modulated signal containing frequency components representative of said electric signal generated by said transducer; and a demodulator connected to said downconverter stage for demodulating said second modulated signal to obtain said electric signal; and a speaker for converting said electric signal to said audio signal; wherein said components of said transmitter circuit are driven by a voltage substantially equal to said unregulated predetermined DC output voltage so that one of a voltage regulator voltage step-up converter and voltage step-down converter is not required for transmitter circuit operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A low power communication device for transmitting and receiving frequency modulated radio signals in the 900 MHz band for monitoring an audio signal from a remote location, said device comprising:
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a transmitter unit having a housing defining a transmitter cavity therein; a transducer mounted to said housing for converting the audio signal to an electric signal; a transmitter circuit disposed in said transmitter cavity, said circuit including, an amplifier component connected to said transducer for amplifying said electric signal; and a frequency modulator component having a carrier frequency within the range of 900 to 928 MHz, said carrier frequency being modulated by said amplified electric signal for generating a modulated electric signal; a transmitter antenna connected to said modulator for radiating said modulated electric signal; a receiver unit having a housing defining a receiver cavity therein and a pair of terminals directly connected to a power source having a predetermined unregulated DC output voltage; a receiver antenna mounted to said housing for receiving said radiated modulated electric signal; a receiver circuit disposed in said receiver cavity and connected to said pair of terminals, said receiver circuit including, a downconverter stage connected to said receiver antenna for converting said modulated electric signal to a second modulated signal having a frequency less than said carrier frequency, said second modulated signal containing frequency components representative of said electric signal generated by said transducer; and a demodulator connected to said downconverter stage for demodulating said second modulated signal to obtain said electric signal; and a speaker for converting said electric signal to said audio signal; wherein said downconverter stage and said demodulator of said receiver circuit are driven by a voltage substantially equal to said unregulated predetermined DC output voltage so that one of a voltage regulator, voltage step-up converter and voltage step-down converter is not required for receiver circuit operation. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A low power communication device for transmitting and receiving frequency modulated radio signals in the 900 MHz band for monitoring an audio signal from a remote location, said device comprising:
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a transmitter unit having a housing defining a transmitter cavity therein and a first pair of terminals directly connected to a power source having a first unregulated predetermined DC output voltage; a transducer mounted to said housing for converting the audio signal to an electric signal; a transmitter circuit disposed in said transmitter cavity and connected to said first pair of terminals, said circuit including, an amplifier component connected to said transducer for amplifying said electric signal; and a frequency modulator component having a carrier frequency within the range of 900 to 928 MHz, said carrier frequency being modulated by said amplified electric signal for generating a modulated electric signal; a transmitter antenna connected to said modulator for radiating said modulated electric signal; wherein said components of said transmitter circuit are powered by a voltage substantially equal to said first unregulated predetermined DC output voltage so that one of a voltage regulator, voltage step-up converter and voltage step-down converter is not required for transmitter circuit operation; a receiver unit having a housing defining a receiver cavity therein and a second pair of terminals directly connected to a power source having a second unregulated predetermined DC output voltage; a receiver antenna mounted to said housing for receiving said radiated modulated electric signal; a receiver circuit disposed in said receiver cavity and connected to said second pair of terminals, said receiver circuit including, a downconverter stage connected to said receiver antenna for converting said modulated electric signal to a second modulated signal having a frequency less than said carrier frequency, said second modulated signal containing frequency components representative of said electric signal generated by said transducer; and a demodulator connected to said downconverter stage for demodulating said second modulated signal to obtain said electric signal; and a speaker for converting said electric signal to said audio signal; wherein said downconverter stage and said demodulator of said receiver circuit are powered by a voltage substantially equal to said second unregulated predetermined DC output voltage so that one of a voltage regulator, voltage step-up converter and voltage step-down converter is not required for receiver circuit operation. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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Specification