2 results about "Delay unit" patented technology

The invention discloses an automatic frequency calibration circuit for realizing an active RC (Resistance Capacitance) filter by utilizing capacitance delay characteristics, which comprises a delay unit and a digital part, wherein a capacitor array in an active RC filter circuit is fully copied by the capacitor array in the delay unit; the capacitor arrays have the same control word signal; a frequency division signal generated by the digital part is delayed by the delay unit, thereby obtaining a delayed signal; the delayed signal is fed back to the digital part; a counter is used for counting within the delay time; an obtained counting value is compared with an expected reference counting value window; the control word signal of the capacitor array is correspondingly adjusted; and the adjusted control word signal of the capacitor array is used for automatically calibrating a frequency response of the active RC filter. The automatic frequency calibration circuit has the advantages that the change in the frequency response of the active RC filter circuit caused by the influences of technology, power voltage and temperature is avoided.