Patent ID: 6337913
Filing Date: 2002-01-08
Classification: H03J,H04H

Abstract:
A wireless transmitter/receiver circuit system comprising transmitter circuit and a receiver circuit, said transmitter circuit comprising an audio amplifier, a deviation limit, a pre-emphasis, a stereo multiplexer, a radio frequency oscillation driver, a battery charger, a channel select, a radio frequency oscillator, a channel display, and a video input, said receiver circuit comprising an antenna radio frequency amplifier, a mixer, a scan driver, a first frequency demultiplier having a 1 GHzËœ2 GHz local oscillator, a 100KËœ300 MHz local oscillator, a first IF (intermediate frequency) pass, a second IF (intermediate frequency) amplifier, an AGC (automatic gain control), a FM (frequency modulation) detector, a stereo decode, a de emphasis, a volume control, a power driver and mute, speakers, a channel select, a video output, and a video display, wherein:said stereo multiplexer of said transmitter circuit comprises a pilot oscillator for accurate signal guiding, and a 32KËœ1 MHz select for encrypting transmitting signal to prevent a mixing of noises; a level control power standby is connected between said radio frequency driver and the circuit of said deviation limit and said pre emphasis and said stereo multiplexer, said level control power standby being comprised of three transistors and a diode and connected to a compression amplifier of said deviation limit and then transistors of said deviation limit, the transistors of said level control power standby being turned on/off subject to the presence of the signal to be transmitted; said radio frequency oscillation driver is covered within a metal shell, having an antenna directly coupled to said metal shell and spaced from an oscillator thereof at a distance, enabling air in said metal shell between the oscillator and the antenna to achieve a capacity effect to let the antenna to be directly coupled to the oscillator; said receiver circuit comprises a VCO (voltage controlled oscillator) tone and a pilot select, said VCO tone and said pilot select being connected to said FM detector, the output value of said pilot select is set subject to the encrypted value from said transmitter unit and transmitted through said FB detector to said first frequency demultiplier; said first frequency demultiplier comprises a digital logic, a scan driver, and a mixer, and receives signal from said second FM amplifier and said AGC and signal from said FM detector and said stereo decode, so as to automatically scan, trace, compare, and handle signals from said transmitter circuit, and to output a control signal to said pilot make test, causing said stereo decode to provide the matched transmitting frequency for said de emphasis for accurate working.