Uniden America Corporation

Silicon Wave, Inc.

Uniden Financial, Inc.

Stephen J Brown

Hoi Nguyen

Andrew Xavier Estrada

Mark Vernon Lane

Terrance Raymond Bourk

Christopher Dennis Hull

Jorge Alberto Grilo

Patrick Joseph Murphy

Steven R Norsworthy

An apparatus for receiving signals includes a low noise amplifier (LNA) configured to receive a radio frequency (RF) signal. An I/Q direct down converter is coupled to the LNA. The I/Q direct down converter is configured to split the RF signal into real and imaginary components and to down convert the real and imaginary components directly to baseband signals. A local oscillator (LO) is coupled to the I/Q direct down converter and is configured to drive the I/Q direct down converter. First and second filters are coupled to the I/Q direct down converter. The first and second filters are configured to filter the down converted real and imaginary components, respectively. First and second analog-to-digital converters (ADCs) are coupled to the first and second filters, respectively. The first and second ADCs are configured to convert the real and imaginary components into digital signals. The first and second ADCs have a dynamic range that is wide enough to convert the filtered, down converted real and imaginary components to digital signals without using variable gain on the filtered and down converted real and imaginary components. An apparatus for use in wireless communications includes a radio, a modem and a controller integrated onto a single integrated circuit (IC). The radio includes a receiver for receiving data and a transmitter for transmitting data. The modem is coupled to the radio and is configured to demodulate received data and modulate data for transmission. The controller is coupled to the modem and includes a digital interface for external communications through which received data and data for transmission is sent, a connection state machine configured to accept commands through the digital interface and to respond to the commands by initiating a sequence, and a receive/transmit state machine configured to perform state control of the radio in response to the initiated sequence.

Apparatus and method for wireless communications

A power control circuit for use with a closed loop transmitter such as a cellular telephone. The inventive circuit includes an amplifier for varying the output power level of the transmitter output signal. The amplifier includes an input terminal and a gain control terminal. The transmitter output is fed back to the gain control terminal of the amplifier by a feedback loop. The feedback loop includes circuitry for adjusting the response thereof in response to a loop gain control signal. A control system is included for receiving a power level control signal over a predetermined range of transmitter output power levels and providing the loop gain control signal in response thereto whereby the feedback loop has a linear gain response over the predetermined range of output power levels. In the illustrative embodiment, the system is adapted for use in a mobile station of a cellular telephone system to which a power level control signal is supplied by a base station thereof. The amplifier includes a first variable gain amplifier. The feedback loop includes a detector, a second variable gain amplifier or variable attenuator, an integrator implemented with a low pass filter, and a comparator. The second variable gain amplifier is digitally controlled by a microprocessor in the control system to adjust the output of the detector. The microprocessor controls the gain of the second variable gain amplifier so that the output thereof is linear over a range of power level control signals applied by a base station. The output of the power detector is compared to a reference voltage supplied by the control system in response to the power level control signal applied by the base station. The output of the comparator is input to the gain control input of the first variable gain amplifier.

Closed loop transmitter with improved stability and accuracy over a wide range of power levels having means for maintaining constant loop gain

A power control circuit for use with a closed loop transmitter such as a cellular telephone. The inventive circuit includes a first element for providing a transmitter output signal. A second element serves to receive a power level signal. A third element is included for adjusting the transmitter output signal in response to the power level signal in accordance with a first scale factor over a first range if the power level signal is below a first threshold and for adjusting the transmitter output signal in response to the power level signal in accordance with a second scale factor over a second range if the power level signal is not below the first threshold. In the illustrative embodiment, the system is adapted for use in a mobile station of a cellular telephone system to which a power level control signal is supplied by a base station thereof. The first element is a variable gain amplifier, the second element is a microprocessor. The third element includes a digital-to-analog converter, a detector for detecting a peak amplitude of the output, a subtractor for subtracting the output of the detector from a reference voltage. The reference voltage is supplied by the digital-to-analog converter. The output of the subtractor is input to a variable gain control input of the variable gain amplifier. The invention affords an improved design for a cellular telephone transmitter including a modulator for upconverting in input signal; a variable gain amplifier, a feedback loop coupled to the output of the amplifier and a gain varying input thereof and a circuit for adjusting the response of the feedback loop in response to changes in an applied control voltage.

Closed loop transmitter with DAC sensitivity adjusted to detector nonlinearity

Growing community of inventors

San Diego, CA, United States of America

Stephen J Brown