Abstract: A status monitor circuit for detecting the status of a DC power supply for charging a battery is provided. The status monitor circuit includes a DC bus and a failure indicator circuit. The DC bus is coupled between the DC power supply and the battery. The failure indicator circuit is configured to detect a DC voltage generated by the DC power supply on the DC bus. The failure indicator circuit includes a failure indicator and a relay configured to activate the failure indicator when the DC voltage is below a failure threshold voltage.

Abstract: A status monitor circuit for detecting the status of a DC power supply for charging a battery is provided. The status monitor circuit includes a DC bus and a failure indicator circuit. The DC bus is coupled between the DC power supply and the battery. The failure indicator circuit is configured to detect a DC voltage generated by the DC power supply on the DC bus. The failure indicator circuit includes a failure indicator and a relay configured to activate the failure indicator when the DC voltage is below a failure threshold voltage.

Abstract: A method of encoding speech by analyzing a digitized speech signal to determine excitation parameters for the digitized speech signal is disclosed. The method includes dividing the digitized speech signal into at least two frequency bands, determining a first preliminary excitation parameter by performing a nonlinear operation on at least one of the frequency band signals to produce a modified frequency band signal and determining the first preliminary excitation parameter using the modified frequency band signal, determining a second preliminary excitation parameter using a method different from the first method, and using the first and second preliminary excitation parameters to determine an excitation parameter for the digitized speech signal. The method is useful in encoding speech. Speech synthesized using the parameters estimated based on the invention generates high quality speech at various bit rates useful for applications such as satellite voice communication.

Abstract: A method of encoding speech analyzes a digitized speech signal to determine excitation parameters for the digitized speech signal. The method includes dividing the digitized speech signal into at least two frequency bands, performing a nonlinear operation on at least one of the frequency bands to produce a modified frequency band, and determining whether the modified frequency band is voiced or unvoiced. The nonlinear operation is an operation that emphasizes a fundamental frequency of the digitized speech signal so that the modified frequency band signal includes a component corresponding to the fundamental frequency even when the at least one frequency band signal does not include such a component.