Abstract: The invention generally relates to stabilizing an amplifier. In one aspect, a stabilization module that is in electrical communication with the amplifier is provided. The stabilization module includes both an open loop control system and a closed loop control system. The open loop control system is used to modify at least one characteristic of an input signal received by the stabilization module and to pass control to the closed loop control system. The closed loop control system is then used to modify the at least one characteristic of the input signal. The modified input signal is provided to the amplifier.

Abstract: The invention generally relates to stabilizing an amplifier. In one aspect, a stabilization module that is in electrical communication with the amplifier is provided. The stabilization module includes both an open loop control system and a closed loop control system. The open loop control system is used to modify at least one characteristic of an input signal received by the stabilization module and to pass control to the closed loop control system. The closed loop control system is then used to modify the at least one characteristic of the input signal. The modified input signal is provided to the amplifier.

Abstract: A signal converter which inputs a time domain signal having a relatively large bandwidth and which outputs a frequency domain signal is disclosed. The time domain input signal is split into two identical portions. One portion is delayed relative to the other portion to produce an unambiguous relative phase shift which varies as a function of frequency. The two portions are sampled at a rate which is significantly below the Nyquist rate for the bandwidth. Two conventional discrete Fourier transforms (DFT) processors transform the two portions into two frequency domain data arrays. A post-DFT operation resolves the relative phase differences to expand the bandwidth which results from the low sampling rate and to eliminate aliasing.

Abstract: An automatic frequency control circuit having the ability to resolve the frequency of an incoming signal to an extreme level of accuracy and to tolerate amplitude and pulse modulation on the incoming signal is disclosed. Two negative feedback loops are utilized. A coarse adjustment feedback loop resolves the frequency of the incoming signal to within the authority of a fine adjustment feedback loop. A computer is a common element of both loops and makes decisions regarding whether to resolve incoming a signal frequency using the coarse or the fine adjustment loops. Phase differences between a signal derived from the incoming signal and a reference signal are sampled at controllable time intervals apart to determine frequency adjustments within the fine adjustment loop.