Abstract: A zero intermediate frequency radio device has an antenna for receiving a radio frequency signal, and a frequency down converter for down converting the received radio frequency signal to a zero intermediate frequency signal. The radio device further has controllable amplifier stages, controllable AC-coupling stages, controllable filter stages, and a received signal strength indicator. A signal resolving range of the received signal strength indicator is below a high dynamic range of the received radio frequency signal. The radio device further has an automatic gain controller. The automatic gain controller initially sets the gain of the Rx path of the radio device to a maximum of minimum gain, and then waits for DC-offsets in the Rx path to cancel. If, at maximum or minimum gain, a reading of the received signal strength indicator is within a particular range, the automatic gain controller sets the gain to the reading. Then, automatic gain control settles.

Abstract: Systems and methods can be used to maintain operation of a receiver co-located with a transmitter in a communication device and susceptible to interference therefrom by anticipating the intervals during which the transmitter is active (i.e., transmitting) and then desensitizing the receiver during that interval. Although the receiver may operate in a reduced capacity due to periodic desensitization, the adverse effects of interference generated by the transmitter can be avoided. For example, interference from the transmitter can cause variables, such as the gain applied by an automatic gain control module at the receiver input, to deviate from a normal operating or steady state value, which must then be recovered when the interference from the transmitter ceases.

Abstract: An apparatus (150), system (100) and method (400-440) are illustrated for power amplification of an input signal to produce a substantially linear amplified output signal, for broadband wireless applications such as 3G cellular and broadband CDMA systems, without causing significant intermodulation distortion or spectral growth. The preferred system (100) embodiment includes an envelope detector (110) to determine an envelope detector voltage from the input signal; a tracking power supply (120) to determine a supply voltage, preferably as a substantially quantized replica of the envelope detector voltage; an input signal conditioner (150) to determine, in response to the supply voltage, a corresponding phase adjustment and a corresponding gain adjustment, and to modify the input signal using the corresponding phase adjustment and the corresponding gain adjustment to produce a conditioned input signal for power amplification.

Abstract: A receiver comprising analog signal processing means, intermodulation interference detection means and an automatic gain control circuit for controlling the gain of said analog signal processing means, in which an output of the analog signal processing means is coupled through frequency selective means for channel selection and an amplitude detector to a first terminal of the intermodulation interference detection means. A signal generator is used to generate a gain modulation signal being coupled to a gain control input of said analog signal processing means as well as to a second terminal of the intermodulation interference detection means.

Abstract: An apparatus for use in a receiver in a communication system in which signals cover a wide range of power levels. The apparatus provides reduced power consumption without sacrificing receiver sensitivity by using an amplifier having a fixed, relatively narrow dynamic range that can by selectively positioned to accommodate the wide range of power levels. The amplifier is placed earlier in the receiver signal processing chain than comparable amplifiers in conventional receivers.

Abstract: An intelligent gain controller operates to control the gain in each one of wideband uplink and downlink signal paths. Weak desired signals, within each wideband signal path, are detected using a narrowband down converter and detector, and these desired signals monitored by the micro controller. Based on the monitored signals, the micro controller operates, under control of suitable software implementing an Adaptive Control Algorithm, to adjust the gain in each of the uplink and downlink paths in order to dynamically optimize performance.

Abstract: A method of adjusting transmit power in a CDMA portable phone to maintain adjacent channel power rejection (ACPR) passing margin includes the steps of amplifying a first radio frequency (RF) signal according to a first gain to produce a second RF signal, and amplifying the second RF signal according to a second gain to produce a third RF signal. A desired power level of the third RF signal is determined and a new gain value is computed from the desired power level. The first gain value is adjusted to the new value. A system for adjusting transmit power in a CDMA portable phone to maintain adjacent channel power rejection (ACPR) passing margin includes an automatic gain control (AGC) amplifier having an AGC input terminal, an AGC output terminal, and a control signal input terminal. The system also includes a power amplifier (PA) having a PA input terminal and a PA output terminal, wherein the PA input terminal is connected to the AGC output terminal.

Abstract: In a radio front-end circuit having at least two amplifier-mixer cascades, the amplifiers are switched on or off via the mixers. By switching between the amplifier-mixer cascades, the power consumption is lowered.

Abstract: A method of electronically tracking and locating a very large number of objects such as, but not limited to, personal case files in health care, law, or human services systems is described. Each object to be tracked has an attached miniature radio transmitter called a tag which sends a coded signal to a network of receiver base stations with limited but overlapping reception ranges. Each receiver base station places in its own memory the time at which a record enters its range, remains in range, and the time at which it leaves. The various receiver base stations are interconnected to a host computer. By polling the memories of each receiver base station, the computer is able to determine the current location of any record.

Abstract: A controlled receive device is disclosed having an amplifier circuit, which receives an input signal, and a control circuit which receives the input signal and outputs a controlled signal to a receiver. The receiver outputs an output signal. A controller varies the gain of the amplifier circuit in response to levels of the controlled signal and the output signal. The control circuit outputs a controlled indicator signal indicative of a level of the controlled signal and the receiver outputs an output indicator signal indicative of the output signal level. The controlled indicator signal and the output indicator signal are compared using comparators, to respective reference or threshold levels for producing control signals used by the controller for varying the amplifier gain.

Abstract: A method and system for intelligently controlling the linearity of an RF receiver by selectively increasing the effective third-order intercept point (IP3) value of a low noise amplifier (LNA)/mixer channel only when needed. A control signal is generated based on mode of operation (receive mode); received signal strength information (RSSI); transmit channel output power, as indicated by a Tx automatic gain control (AGC) signal; and the true received signal strength, as indicated by the pilot signal-to-noise ratio in a CDMA system. The control signal is then used to selectively increase the bias current—and thus linearity—of the LNA/mixer channel, or to select one of several LNAs having differing IP3 values to effectively increase the linearity of the LNA/mixer channel.

Abstract: An intermediate-frequency signal is fed to a demodulated-signal processing circuit through a variable gain circuit, an active filter, and a limiter. An RSSI output signal responsive to a received signal level is obtained through a low-pass filter by detecting the output of each stage of the limiter at a detector and by summing the output of the detector at an adder. The linearity of the RSSI output signal responsive to the received signal level is improved by feeding, via a coefficient multiplier to the adder, the control signal of a level detector which detects the control signal of the variable gain circuit, which limits the signal input to the active filter.

Abstract: An RF signal received from an antenna is supplied to an RF portion. The RF portion mixes down the RF signal to an IF signal. An RSSI circuit of an automatic gain controlling circuit portion converts the received RF signal into a DC component and detects the electric field intensity of the received signal. A level determining unit has two threshold values of the input level. The level determining unit controls the variable amount of a gain varying unit corresponding to the input level. An averaging process circuit averages a digital signal in a predetermined time period T and controls the variable amount of the gain varying unit 3 so that the average value converges at a digital value with n bits that represent a predetermined amplitude level. A BB portion demodulates the digital signal that has been modulated on the transmitting side to original information.

Abstract: A transmission apparatus with reduced current consumption for a mobile terminal is disclosed. The transmission apparatus includes an automatic gain control (AGC) amplifier for AGC-amplifying an input baseband signal; an attenuator for attenuating an output signal of the AGC amplifier; a multiplier for multiplying an output signal of the attenuator by a carrier frequency signal to convert the signal into a radio frequency (RF) signal; a first filter for filtering an output signal of the multiplier; a drive amplifier for amplifying an output signal of the first filter; a second filter for filtering an output signal of the drive amplifier; a power amplifier for amplifying an output signal of the second filter; and an antenna. When output power of the mobile terminal is lower than predetermined maximum output power of the AGC amplifier, the output signal of the AGC amplifier is transmitted through the multiplier, the first filter and the antenna.

Abstract: A gain control circuit comprises a variable gain circuit having a predetermined gain control range and a control voltage supply circuit for supplying an internal control voltage to the variable gain circuit as a gain control signal. In this gain control circuit, the control voltage supply circuit generates the internal control voltage in response to an external control voltage as to compensate a linearity of the variable gain circuit to an extent of the external control voltage where the variable gain circuit loses a linearity. This gain control circuit is applied to an AGC circuit of a transmitting stage in a CDMA type mobile phone.

Abstract: An antenna tuning circuit 1 is tuned to a received RF signal, and outputs a signal into an RF amplifying circuit 2 for amplification. After amplification, the circuit 2 outputs a signal to an RF tuning circuit 3, which is then tuned to the supplied signal. Since the frequency of a local oscillation signal is set according to the frequency of an object station, the RF signal of an object station is converted by a mixing circuit 4 into an IF signal having a predetermined center frequency. Also, the tuning frequency of the antenna tuning circuit 1 is adjusted to match the frequency of an object station. When disturbance stations with strong field intensity are received, field intensity of a received signal exceeds a predetermined level and a dumping control circuit 9 is activated to generate a dumping signal. In response to the dumping signal, a dumping circuit 10 is turned on, as a result of which an output signal of the antenna tuning circuit 1 is attenuated.