Abstract: A telephone includes a transmit channel and a receive channel, each including a bank of sub-band filters having a VAD coupled one to each sub-band filter. Each VAD measures the spectral energy in a sub-band, compares the spectral energy to a first threshold, and produces an output signal representative of whether or not the first threshold is exceeded. The voice activity detector also includes a threshold circuit for calculating a dynamically adjustable noise threshold based upon averaged measured spectral energy. A wide band or system VAD monitors echo canceling circuitry to detect voice activity and double talk. A dynamic balance control circuit maintains the transmit and receive channels in a predetermined energy ratio during double talk.

Abstract: A telephone includes a transmit channel and a receive channel, each including a bank of sub-band filters having a VAD coupled one to each sub-band filter. Each VAD measures the spectral energy in a sub-band, compares the spectral energy to a first threshold, and produces an output signal representative of whether or not the first threshold is exceeded. The voice activity detector also includes a threshold circuit for calculating a dynamically adjustable noise threshold based upon averaged measured spectral energy. A wide band or system VAD monitors echo canceling circuitry to detect voice activity and double talk. A dynamic balance control circuit maintains the transmit and receive channels in a predetermined energy ratio during double talk.

Abstract: A user interface for directing the programming of operating parameters for patient blood pressure testing into and downloading blood pressure data from ambulatory patient blood pressure monitoring units. The user interface operates on a system comprising a plurality of microprocessor based, ambulatory blood pressure measuring patient units, an office control unit, and a data processing center, typically accessed over telephone lines. An office control unit is used to program patient units with test regimens for specific patients. The control units are also used to download data from the patient units and to transfer the data, along with patient identifying data, to the central data processing facility. The office control unit includes local memory which stores various interface routines, a microprocessor for executing the routines, a 12-character keypad allowing input of integers and a display for displaying prompts to the user.