Abstract: A circuit for detecting when a derivative signal has reached its operating level during power-up of an integrated circuit includes a reset circuit, a latch circuit and a node monitoring circuit. The reset circuit, latch circuit and node monitoring circuit are all connected at a node. When power-up starts, the reset circuit causes the level at the node to be driven to an initial level corresponding to the level provided by an external power source. In response to this initial level at the node, the latch circuit generates an output signal with a level indicating that the derivative signal has not yet reached its operating level. The node monitoring circuit monitors the level of the derivative signal. When the level of the derivative signal reaches its operating level, the node monitoring circuit causes the level at the node to change so as to cause the latch circuit to generate the output signal with a level that indicates that the derivative signal has reached its operating level.

Abstract: A regulator system includes first and second voltage sensing circuits coupled to a voltage generator control circuit. The first and second voltage sensing circuits are configured to monitor the voltage generated by the on-chip voltage generator (i.e., the on-chip supply voltage) and detect when the on-chip supply voltage reaches thresholds that are predetermined to define a desired range of the on-chip supply voltage. The voltage generator control circuit receives voltage sense signals from the voltage sense circuits and, in response, asserts or de-asserts a control signal received by the on-chip voltage generator so as to activate or de-activate the on-chip voltage generator to maintain the on-chip supply voltage within the desired range. The voltage generator control circuit introduces hysteresis in the generation of the control signal provided to the on-chip voltage generator.

Abstract: The parameters of a digital signal are extracted by the application of autocorrelation and crosscorrelation techniques to effectively measure the frequency and time behavior of a digital signal. The method employs digital autocorrelation and crosscorrelation to determine these parameters. Autocorrelation allows the measurement of signal frequency by measurement of instantaneous signal phase. Crosscorrelation allows measurement of relative phase between two or more signals in two or more channels by measurement of instantaneous phase and by referencing the instantaneous phase to the autocorrelation function. The autocorrelation function and crosscorrelation function preserve relative amplitude and phase. Measurement of relative amplitude and phase allows direction finding calculation for any current class of system that uses amplitude and/or phase to derive angle or arrival.