US 5,034,962 A · Voice-band signal processor

Abstract

A voice-band signal processor uses a DSP to filter digital transmit and receive voice-band signals, and has oversampling D/A and A/D converters with a frequency converter to convert between the oversampling rate and the DSP rate. An interpolator converts the filtered receive voice-band signal to a pseudo-analog signal that can be sampled by a demodulator in synchronization with a regenerated receive sampling clock, thus enabling correct operation even when the transmit and receive sampling clock rates do not match. In addition, the voice-band signal processor contains a status register circuit connected to flag registers in the DSP, enabling a host computer to read and set flag values that control the operating mode of the voice-band signal processor. The voice-band signal processor can thus be switched between half duplex and full duplex operation, or between different bit rates.

Claims15

Dependent claims

A voice-band signal processor for converting a digital transmit voice-band signal to an analog transmit voice-band signal, and for converting an analog receive voice-band signal to a pseudo-analog receive voice-band signal, comprising:

a digital signal processor for receiving said digital transmit voice-band signal and performing a digital filtering process to generate a filtered digital transmit voice-band signal, and for receiving a digital receive voice-band signal and performing a digital filtering process to generate a filtered digital receive voice-band signal;
a D/A converter coupled to said digital signal processor, for receiving said filtered digital transmit voice-band signal and converting it to analog form to generate said analog transmit voice-band signal;
an A/D converter coupled to said digital signal processor, for receiving said analog receive voice-band signal and converting it to digital form to generate said digital receive voice-band signal;
and
an interpolator coupled to said digital signal processor, for receiving said filtered digital receive voice-band signal and performing an interpolation process to generate said pseudo-analog receive voice-band signal.

2 more elements

A voice-band signal processor for converting a digital transmit voice-band signal to an analog transmit voice-band signal, for converting an analog receive voice-band signal to a pseudo-analog receive voice-band signal, comprising:

a digital signal processor for receiving said digital transmit voice-band signal and performing a digital filtering process to generate a filtered digital transmit voice-band signal, and for receiving a digital receive voice-band signal and performing a digital filtering process to generate a filtered digital receive voice-band signal;
a D/A converter coupled to said digital signal processor, for receiving said filtered digital transmit voice-band signal and converting it to analog form to generate said analog transmit voice-band signal;
and
an A/D converter coupled to said digital signal processor, for receiving said analog receive voice-band signal and converting it to digital form to generate said digital receive voice-band signal;
wherein said digital signal processor comprises one or more flag registers for storing information pertaining to the communication mode.

2 more elements

Dependencies are inferred from the claim text.

Voice-band signal processor

Life of this patent

Voice-band signal processor

Life of this patent

Abstract

Claims15