Abstract: A differential track and hold amplifier circuit (200) is provided. The track and hold amplifier includes an input transconductance amplifier (212), an output amplifier (111), and a second transconductance amplifier (214). The track and hold circuit further includes a switching circuit (108) for coupling the output of the input transconductance amplifier to a capacitor (110) in the output stage of the track and hold circuit during track mode, and for decoupling the capacitor from the input amplifier during hold mode. The track and hold circuit further includes a subtractor circuit (103) for reducing a common mode voltage of the output of the input transconductance amplifier, thereby maintaining a stable voltage across the capacitor during hold mode. Further, during hold mode, the second transconductance amplifier acts in a negative feedback configuration to reduce the gain of the input amplifier to attenuate its output signal.

Abstract: A frequency discriminator circuit is provided having increased resolution for detecting the frequency of a data input signal above and below a predetermined frequency threshold by monitoring a count value. The output signal of the frequency discriminator circuit remains at a first logic state provided the count value is reset by the data input signal before reaching a predetermined count value signifying that the frequency of data input signal is above the predetermined frequency threshold. The output signal of the frequency discriminator circuit switches to a second logic state if the count value reaches the predetermined count value before receiving a reset signal thereby indicating that the frequency of data input signal is below the predetermined frequency threshold.