Abstract: A system and method for implementing a cellular radio transmitter device comprises a first oscillator device for generating a first oscillator output signal, a second oscillator device for generating a second oscillator output signal, a power amplifier for amplifying the second oscillator output signal to obtain a transmit signal, a mixer device for combining the first oscillator output signal and the transmit signal to produce a mixer output signal, a phase comparator for comparing the mixer output signal and a transmitter input signal and responsively generating a control signal to control the transmit oscillator, and a feedback path for adding the mixer output signal to the transmitter input signal to compensate for distortion present in the transmit signal.

Abstract: A data communication system receives data signals transmitted via a signal path and applies to the received signal a high-pass function including a low-pass filter and a summing circuit. The signal is low-pass filtered, and the summing circuit subtracts the filtered signal from the received signal to generate a high-pass signal, which is summed with a quantized-feedback signal to generate a recovered data signal. The quantized-feedback signal is provided by applying to the recovered data signal a low-pass function having a transfer function which is substantially complementary to the transfer function of the high-pass function. The low-pass function low-pass filters the recovered data signal to generate the quantized-feedback signal.

Abstract: A digital, radio-frequency (RF) transceiver is modified by coupling an infra-red (IR) communication subsystem thereto. The subsystem includes an IR transmitter and receiver which may be coupled selectably by a switch to a data signal channel or source in the transceiver. Preferably, the IR receiver includes an inductor and a diode coupled in parallel, such that the IR receiver detects an IR signal, in significant part, by resonating such signal substantially at a detection or RF baseband frequency.

Abstract: A PCMCIA package with a shielded package for radio electronics is inserted into a selected PCMCIA slot with only one edge of the shielded package being immediately accessible. A microwave and radio frequency transparent containment is mounted at a selected edge of the shielded package. An antenna is mounted within the microwave and radio frequency transparent containment for electromagnetic communication through the microwave and radio frequency transparent containment.

Abstract: A write driver control circuit controls the voltage level input to a switch circuit, providing increased range for head voltage swings and fast current switching, providing a write driver circuit with a variable voltage level which tracks the write current, as well as temperature and process variations, but which is independent of power supply voltages.

Abstract: An amplifier circuit providing high power efficiency and an improved phase margin includes a transconductance input stage, one output of which is connected to an input of a class AB amplifier gain stage to form a compensation node, and the other output of which drives a current gain means, with the outputs of the current gain means and the class AB amplifier forming a current summing output node that is coupled to the compensation node through a compensation capacitor. The phase margin of the amplifier circuit is optimized by selecting the gain of the current gain means to be approximately equal to one plus the ratio of the capacitance of the load to the capacitance of the compensation capacitor.

Abstract: A method and apparatus for providing a lower frequency signal with reference to a higher frequency signal are disclosed. The apparatus of the invention comprises an oscillating signal generator, an integer logical divider, and a signal combiner. The signal generator receives an input voltage and, in response thereto, generates a first output oscillating signal and a second output oscillating signal, both having a first frequency. The two oscillating signals are separated by a ninety-degree phase shift. The integer logical divider receives the two oscillating signals and provides two output divided signals in response. The first divided signal is representative of the first oscillating signal except that its frequency is one-third the frequency of the first oscillating signal. Likewise, the second divided signal is representative of the second oscillating signal except that its frequency is one-third that of the second oscillating signal.