Abstract: A direct conversion receiver includes a differential mode mixer with first and second DC coupled amplifier chains, the first and second amplifier chains are connected to the mixer for amplifying differential signals. A common mode offset correction circuit is coupled to the first and second amplifier chains so as to feedback correction signals that cause common mode DC offsets in the first and second amplifier chains to be equal and opposite. A differential mode offset correction circuit is coupled to the first and second amplifier chains so as to feedback correction signals that cause differential mode DC offsets in the first and second amplifier chains to be equal. The only solution for the two correction circuits is zero DC offset.

Abstract: A low noise oscillator for use in a radio which provides an output signal with high signal-to-noise ratio. The low noise oscillator includes a voltage controlled oscillator which produces an intermediate sinusoidal voltage signal in response to a DC tuning voltage. The voltage controlled oscillator includes a varactor and junction field effect transistor. The low noise oscillator also includes a buffer amplifier which receives the intermediate sinusoidal voltage signal from a tapped microstrip of the voltage controlled oscillator and produces a highly stable output signal proportional to the DC tuning voltage applied to the input of the low noise oscillator. The buffer amplifier employs a dual gate Gallium Arsenide field effect transistor.

Abstract: An apparatus and method is disclosed for operating a modulus control loop of an LSI a phase locked loop integrated circuit (or descrete equivalent) and a dual modulus prescaler at higher frequencies. This is accomplished through the use of a flip flop whose input is the modulus control output from the synthesizer IC and whose clock input is provided by the output of the prescaler. This greatly extends the time available to shift the prescaler modulus control insuring that the control signals will not be missed and increasing the available frequencies that the modulus control loop may operate at.