Motorola Corporation

Charles A Backof

David L Muri

Robert E Stengel

A phase demodulator (101) is used for sensing the phase.sub.-- angle of a phasor represented by the I and Q signals by first producing the analog I and Q signals in a direct conversion receiver (104). A phase generator (106) is used to approximate the angle of the phasor as represented by the I and Q signals by scaling and comparing the magnitudes of the I and Q signals and making decisions based on their relative magnitudes. The scaling includes successive alteration of the magnitude of the I and Q signals.sub.-- depending on their relative magnitudes. A DSP (108) is used to receive this bit stream representation (302) of the phasor and recover the information signal.

Modulator with baseband to phase converter

The communication device (100) operates in full duplex mode by allowing its transmitter (106) to periodically interrupt transmission to allow for a second communication device (702) to send its request-to-transmit signal. This signal is received by the receiver (108) and coupled to a controller (110). The controller (110) dynamically reduces the rate at which it codes the voice in response to the activity on the channel. The coded signal is then coupled to the transmitter (108) for transmission. A sync and control header is included at the beginning of each transmission to allow the two communication devices (100 and 702) to remain in sync and to be aware of the coding rate each of the communication devices (100 and 702) has employed in its most recent transmission. With the two communication devices (100 and 702) operating at dynamically adjusted voice coding rates, each occupies the channel for a portion of time in each frame commensurate with the information flow, thereby providing for full duplex operation.

Communication device with time assigned duplex operation

A high efficiency amplitude/phase modulation amplifier circuit (100) includes a first (102) and a second (106) high efficiency amplifier. These amplifiers (102 and 106) amplify two constant amplitude/phase modulated signals. A combiner (104) combines the output signals from the amplifiers (102) and (106) to produce a combined signal to a load (108). Two shunt elements (202 and 204) are included to prevent the reactive components of the combined signal from reaching the amplifiers (102) and (106). With no reactive components reflected back, the amplifiers (102 and 106) can remain non-linear even though they are used to amplify an amplitude/phase modulated signal which includes Amplitude Modulation (AM) components.

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Coral Springs, FL, United States of America

Charles A Backof