CRYSTAL IF FILTER COMPENSATION CIRCUIT
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2001-Nov-01
The temperature shift of a narrow band crystal IF filter follows in general the "Beckman" curve for the par- ticular cut of the quartz crystal. On the basis of this, if a quartz crystal oscillator, using the same cut of the crystal is incorporated in the feedback loop by the means of a mixer, the VCO will shift its frequency in such a way as to compensate for the shift of the center frequency of the filter.