Abstract: A gain circuit includes an analog section with variable gain and a digital section with variable gain. The gain steps for the digital section have a higher resolution than the gain steps for the analog section. In some implementations, gain steps can be achieved much finer than 0.1 db or less without sensitivity to device tolerances.

Abstract: An OFDM wireless transceiver uses a digital automatic gain control (AGC) module. The digital AGC module is configured for setting a gain to an initial gain value for mapping a received wireless signal to a first power value for an input circuit having a prescribed input range. The initial gain value is set relative to the prescribed input range and a prescribed signal to noise ratio. If the digital AGC module determines that the first power value of the received wireless signal does not exceed the prescribed input range, the digital AGC module calculates an optimum gain for the received wireless signal relative to the initial gain value and the first power value; if the first power value exceeds the prescribed input range, the AGC module determines the optimum gain based on setting the gain to a minimum gain value.

Abstract: A signal is received and whether a signal mode of the signal is a first signal mode or a second signal mode is determined. A gain of a variable gain amplifier is adjusted to a first gain value if the signal mode of the signal is determined to be the first signal mode or a second gain value if the signal mode of the signal is determined to be the second signal mode. The signal is amplified with the variable gain amplifier by the first gain value or the second gain value. The signal is converted to a digital signal with an analog to digital converter after the signal is amplified with the variable gain amplifier by the first gain value or the second gain value.

Abstract: Two or more low noise amplifiers are configured to amplify received radio frequency input signals and one or more shared load or source degeneration inductors are configured to be used for each of the two or more low noise amplifiers. Further, the one or more shared inductors can be configured to be used for processing two or more signal bands in a multi-band communication system.

Abstract: A radio frequency receiver includes a passive mixer configured to receive and RF signal and a low input impedance circuit configured to receive the output of the passive mixer.

Abstract: In some implementations, a signal is received at a device and a gain change is detected in a component of the device that affects the signal. A state of an equalizer is adjusted in response to the detected gain change to a first state that reduces transient effects introduced into the signal by one or more components in the device as a result of the gain change. The signal is equalized using the equalizer with the state set to the first state and the state of the equalizer is adjusted from the first state to a second state while equalizing the signal using the equalizer such that the second state passes the signal through the equalizer substantially unchanged.

Abstract: Radio frequency filtering includes receiving a signal and detecting a change in the direct current (DC) offset of the signal or a change in a component that affects the DC offset of the signal. The filtering also includes setting a cut-off frequency of a high-pass filter to a first frequency value in response to the detected change and filtering the signal using the high-pass filter with the cutoff frequency set to the first frequency value. The filtering further includes adjusting the cutoff frequency of the high-pass filter from the first frequency value to a second frequency value while filtering the signal using the high-pass filter where the second frequency value is less than the first frequency value.

Abstract: Two or more low noise amplifiers are configured to amplify received radio frequency input signals and one or more shared load or source degeneration inductors are configured to be used for each of the two or more low noise amplifiers. Further, the one or more shared inductors can be configured to be used for processing two or more signal bands in a multi-band communication system.

Abstract: Generally, implementations provide a circuit framework that uses phase and amplitude modulation with several voltage-controlled-oscillators (VCOs) and corresponding variable gain amplifiers (VGAs) to generate and amplitude and phase modulated signals that are summed to an output signal for a transmitter circuit. The implementations can involve decomposing an input signal into a number of decomposed signals using a signal decomposer component, in which each of decomposed signals includes phase and amplitude information. The signal decomposer component can interact with each of the VCOs and corresponding VGAs to conduct the phase and amplitude modulation for the amplitude and phase modulated signals. The multiple standard transmitter circuit can be used for one or more communication standards, such as Global System for Mobile Communications (GSM), a Wideband Code Division Multiple Access (WCDMA), or High-Speed Uplink Packet Access (HSUPA), among others.

Abstract: A signal is received and whether a signal mode of the signal is a first signal mode or a second signal mode is determined. A gain of a variable gain amplifier is adjusted to a first gain value if the signal mode of the signal is determined to be the first signal mode or a second gain value if the signal mode of the signal is determined to be the second signal mode. The signal is amplified with the variable gain amplifier by the first gain value or the second gain value. The signal is converted to a digital signal with an analog to digital converter after the signal is amplified with the variable gain amplifier by the first gain value or the second gain value.

Abstract: Techniques and systems for receiving a signal at a first component with an adjustable gain, and adjusting the gain of the first component to a first gain value using a first gain step. Amplifying the signal with the first gain value, generating a first amplified signal, and receiving the first amplified signal at a second component with an adjustable gain. Adjusting a gain of the second component to a second gain value using a second gain step. The net gain step is smaller than one of the first or second gain step. Amplifying the first amplified signal with the second gain value to generate a second amplified signal, and receiving the second amplified signal at a filtering component. A transient response introduced by the filtering component on the second amplified signal is smaller than the transient response that would be introduced by the filtering component on the first amplified signal.

Abstract: A gain circuit includes an analog section with variable gain and a digital section with variable gain. The gain steps for the digital section have a higher resolution than the gain steps for the analog section. In some implementations, gain steps can be achieved much finer than 0.1 db or less without sensitivity to device tolerances.

Abstract: A deinterleaver module in an OFDM wireless transceiver includes partitioned memory banks for storage of code word fragments from an interleaved data stream, each code word fragment associated with a prescribed subcarrier frequency. Each code word fragment includes a prescribed number of code word bits based on a prescribed modulation of the interleaved data stream, and the code word bits for each code word fragment are written into respective selected locations of the corresponding memory bank based on the prescribed modulation and the corresponding prescribed subcarrier frequency. The deinterleaver module outputs deinterleaved data from the memory banks based on parallel output of the respective stored code word bits from a selected address of the memory banks.

Abstract: A Viterbi decoder is configured for subtracting each survivor metric for each corresponding encoder state by a prescribed subtraction operator based on a prescribed event. The subtraction of each survivor metric by a prescribed subtraction operator based on a prescribed event minimizes memory requirements in the accumulated metric table by limiting the survivor metric values to a identifiable range. Hence, the Viterbi decoder can be implemented in an economical manner with reduced memory requirements.

Abstract: An OFDM receiver is configured for suppressing pilot energy, and DC energy, from received I and Q components prior to estimating amplitude and phase imbalances of the received I and Q components. Hence, amplitude and phase imbalances can be estimated accurately despite channel fading and frequency variations between the transmitter and receiver.

Abstract: An OFDM receiver has a DC offset estimator configured for determining a DC offset, in I and Q components of a received OFDM signal having been output by an analog front end, based on filtering prescribed subcarrier components from a preamble segment of the I and Q components. The OFDM receiver removes the determined DC offset from the I and Q components, resulting in respective corrected I and Q components having minimal DC offset.

Abstract: An OFDM receiver has an autocorrelation circuit configured for generating autocorrelated power values from samples of received short preamble symbols in a received data packet, and a median filter configured for generating a median autocorrelation value from at least a prescribed minimum number of the autocorrelated signal values. A comparator is configured for detecting a symbol boundary, identifying an end of the short preamble symbols, based on the autocorrelated signal values falling below a threshold that is based on the median autocorrelation value. Hence, the threshold used to identify the symbol boundary is dynamically calculated on a per-packet basis, eliminating errors due to varying energy levels or propagation characteristics from different packet sources; moreover, the median autocorrelation value minimizes effects due to noise components, minimizing false detection errors.

Abstract: An OFDM receiver has an autocorrelation circuit configured for generating an autocorrelation result from samples of received short preamble symbols in a received data packet, where the autocorrelation circuit generates each autocorrelation result based on accumulation of the samples having been received for the short preamble symbols. Hence, by using all received samples of the short preamble symbols, the autocorrelation based on accumulated samples minimizes the effect of noise and provides a more accurate coarse frequency estimation result.

Abstract: A channel estimator, configured for supplying equalization coefficients to a frequency equalizer, is configured for determining equalizer coefficients for a received wireless signal based on a minimum equalization error-based estimation. The channel estimator is configured for identifying first and second long preambles from the received wireless signal, determining an equalization coefficient for a selected frequency based on a minimized cost function for the first and second long preambles relative to a prescribed preamble value for the selected frequency, and supplying the equalization coefficient for the selected frequency to a frequency equalizer for equalization of the received wireless signal.

Abstract: A Viterbi decoder is configured for outputting a prescribed plural number of decoded bit pairs upon execution of each backtracing operation based on accessing a second prescribed number of state history table entries from a surviving state history table. The outputting of more bits per backtrace operation lowers the number of memory accesses, and enables the Viterbi decoder to maintain a high throughput of data flow while maintaining an acceptable bit error rate.