Dual-mode communications processor

Abstract

A dual-mode communications processor disposed to be incorporated within a dual-mode communications device is disclosed herein. The dual-mode communications processor comprises a dual-mode voiceband signal processor having an input port for receiving digitized data. Within the dual-mode voiceband signal processor, first and second signal processing operations are performed upon the digitized data received during operation in first and second modes, respectively. These separate signal processing operations may advantageously be performed using common circuit elements within the dual-mode voiceband signal processor. In an exemplary embodiment the first signal processing operation is performed in accordance with a predefined vocoding algorithm, while the second signal processing operation involves the filtering of the digitized data as prescribed by FM cellular telephone standards. The dual-mode communications processor further includes a digital modulation modem coupled to the dual-mode voiceband signal processor. The digital modulation modem generates digital modulation data using the digitized data processed by the dual-mode voiceband signal processor during operation in the first mode. An FM modulator, also coupled to the dual-mode voiceband signal processor, generates FM modulation data using the digitized data processed by the dual-mode voiceband signal processor during operation in the second mode. A controller is provided for selecting between operation in the first and second modes. A dual-mode port allows the digitized data to be transferred to and from a dual-mode interface buffer over a common signal path during operation in both the first and second modes.