A mismatch detector including a directional device adapted to couple signals across the device and a detector coupled to a port on the directional device and configured to measure a reflected power a second detector coupled to a port on the directional device and configured to measure a transmit power. The mismatch detector may be used in wireless communication devices, including, but not limited to mobile wireless devices, base stations, and communication systems.

Systems and methods for controlling output power in a communication device

The process and apparatus of the present invention limits the output power of a radiotelephone, operating in a cellular system in the preferred embodiment. This ensures the transmitted sidebands and synthesizer phase noise remains within a certain specification. This is accomplished by power detection and a correction accumulator that together generate a gain control signal by limiting the gain adjustment to a maximum value, even when the cell site communicating with the radiotelephone is sending power turn-up commands to the radiotelephone. This process includes dynamically correcting the output level of the transmitter due to gain variations in the transmitter stages or gain control elements.

Reverse link, transmit power correction and limitation in a radiotelephone system

In a TDM/TDMA portable radio communications system, the modulated RF signal transmitted by a portable handset unit is amplified for uplink transmission to a port by an adaptive class AB power amplifier. A class AB amplifier provides the necessary amplification for the low power levels to be output by the portable units, but must be biased just slightly "on" with no signal input for required maximum efficiency and linearity. In order to maintain the amplifier at a proper bias level over changing temperature conditions and free from the effects of device aging and device-to-device variations, the drain current of the amplifier is monitored each frame outside the burst interval in which the portable is transmitting and thus when no signal is present at its input. The drain current is then controlled by adjusting the gate voltage to compensate for any variations.

Adaptive class AB amplifier for TDMA wireless communications systems

An operating voltage applied to a transmitter's power amplifier in a mobile wireless transceiver is dynamically controlled so as to improve the efficiency of the transmitter at all output power levels. In one embodiment, the bias current levels within the transmitter are also varied to optimize the efficiency of the transmitter at all output power levels. In a preferred embodiment, a highly efficient switching regulator is controlled by a control circuit to adjust the operating voltage and/or bias current for the power amplifier in the transmitter. The control circuit has as its input any of a variety of signals which reflect the actual output power of the transmitter, the desired output power, or the output voltage swing of the transmitter.

Battery life extending technique for mobile wireless applications

The specification relates to a radio frequency (RF) power detection circuit for multiple frequency bands. One embodiment of the present invention uses semiconductors as power detection sensors and as temperature compensation devices. Multiple power detection sensor current signals each develop a voltage signal across a common load resistor. Similarly, multiple temperature compensation sensor current signals each develop a voltage signal across a second common load resistor. A detector voltage and a temperature compensation voltage are then processed through common amplification circuitry, producing a signal proportional to sensed transmitted power.

Wide range multiple band RF power detector

An output level control circuit for radio-frequency transmitter which intermittently transmits radio-frequency carrier waves such as seen in the TDMA radio communication system and the digital cellular mobile telephone system. The variable gain amplifier unit of this transmitter amplifies the transmitting signal to a predetermined output power level in response to a control signal, the output power level is detected by a detecting diode which receives the application of a temperature-compensated bias voltage, and the sum of the detected output and the bias voltage becomes the detection output to the control loop. The bias voltage of the detecting diode is stored by bias voltage detection circuit during the off-period of the transmitting signal, an input reference voltage that is supplied in synchronism with the turning-on of the transmitting signal and the stored bias voltage are added by reference signal addition circuit, and the added output is served as the reference voltage that corresponds to the predetermined output power level. A power control circuit generates the control signal in response to the added output and the detection output, and the control signal controls the output power level of the variable gain amplifier unit.

Miyazaki Shinichi

Papers

Output level control circuit for use in RF transmitter

Schaltung zur Ausgangspegelregelung eines HF-Senders

Output-level control circuit in high-frequency transmission