General Instrument Corporation of Delaware

Daniel J Marz

Apparatus for generating two output signals with a selective predetermined constant phase difference therebetween from an input reference signal having a predetermined frequency and phase includes, in one embodiment, a first and a second Programmable Delay, and a first and a second Synthesizer. The input reference signal is provided as separate inputs to the first and second Programmable Delays which generate first and second output signals, respectively, with selective predetermined delay differences therebetween for transmission to the respective first and second Synthesizers. Each of first and second Synthesizers are phase locked loops with a Programmable Divider and an optional Prescaler added to the loop to divide a high frequency output signal generated by a Voltage Controlled Oscillator (VCO) to a frequency of the output signal from the associated Programmable Delay in order to correct for any phase difference between the output signal of the VCO and the input signal from the Programmable Delay. Various embodiments are provided that include a control loop that operates on the first and second output signals to generate a control signal to one of the Programmable Delays for maintaining a predetermined phase difference between the output signals from the apparatus.

Techniques for generating two high frequency signals with a constant

A double conversion frequency converter includes first and second mixing stages. The first mixing stage includes a first programable Local Oscillator (LO) synthesizer and a first mixer, and the second mixing stage includes a second programable LO synthesizer and a second mixer. The first and second LO synthesizers have a wide band tuning range for receiving a separate predetermined reference signal and generating therefrom first and second LO output signals, respectively, which each are changeable by predetermined large frequency steps. The first mixer mixes an input signal to the frequency converter with the first LO output signal for generating a first predetermined mixer output signal. The second mixer mixes a predetermined sideband generated in the first predetermined mixer output signal with the second LO output signal for generating a second predetermined mixer output signal which is use for the output signal for the frequency converter. The predetermined output signal of the frequency converter is changed in small frequency steps (e.g., at least 1 KHz) by concurrently changing each of the first and second LO output signals using large frequency step changes (e.g., at least 125 KHz) whereby the difference between the large frequency steps in the first and second LO output signals is equal to the small frequency step of the predetermined output signal.

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Richboro, PA, United States of America

Daniel J Marz