Delay detection circuit and low-noise oscillation circuit using the same

摘要

The circuit includes a first high frequency mixer which multiplies an oscillation output by a delayed output. The oscillation output is delayed by a predetermined time to generate a first high frequency signal. A second high frequency mixer multiplies the delayed oscillation output by a phase-shifted (24) oscillation output, obtained by a pi/2 radian delay, to generate a second high frequency signal. A first low frequency mixer multiplies the DC and phase-noise components in the first high frequency signal by the phase-noise components in the second high frequency signal to generate a first low frequency signal. A second low frequency mixer multiplies the DC and phase-noise components in the second high frequency signal by the phase-noise components in the first high frequency signal to generate a second low frequency signal. An adder-subtracter responds to the second low frequency signal by removing dependence on the predetermined delay time from primary phase-noise components in the first low frequency signal. A control voltage is generated without dependence.