Abstract: A method for performing channel estimation of an OFDM channel includes, in part, interpolating pilots for sub-channels positioned within a first range of an OFDM symbol, and estimating frequency response of sub-channels positioned within a second range of the OFDM symbol. The first range is defined by subchannels positioned substantially away from channel edges and the second range is defined by subchannels positioned substantially near channel edges. The method optionally includes transforming the pilots from frequency domain into the time-domain, time-domain windowing to obtain a channel impulse response having a multitude of discrete values, estimating the discrete values within the channel impulse response; and transforming the channel impulse response to the frequency domain.

Abstract: An efficient channel estimation system and method provides good performance under high Doppler conditions and is suitable for OFDM systems such as DVB-T. A number of different pilot interpolations techniques enable the estimation of channel for the OFDM systems. For 2k and 4k modes, the channel is estimated using the preceding symbol, the present symbol, and two succeeding symbols. For an 8k mode, only one future symbol is used to estimate the channel.

Abstract: A method for targeted advertisement includes storing a profile tag associated with each user in a device maintained by that user. Each profile tag includes the demographic information of its associated user. A multitude of target tags are also transmitted to the users. Each target tag is associated with an advertiser and includes the demographic information of the users. The advertisements and their corresponding target tags are transmitted and cached in the devices maintained by the users. The number of matches between the target tags and the user profiles are supplied to their respective advertisers. The advertisers use the matching number to modify the prices they are willing to offer for the commercial break. The target tags include information that is used to select one of the cached advertisement for playing during the commercial break.

Abstract: A diversity receiver and methods of diversity combining are described herein. Diversity combining can be implemented in the front-end signal path of a receiver, without the need to digitally demodulate the baseband signals. Each diversity path is downconverted using a common LO. A portion of each downconverted diversity path is filtered and coupled to an input of a correlator. The diversity paths are paired for the purposes of correlation. The output of the correlator is used to adjust the phase of one of the diversity paths. The amplitude of each diversity path can be equalized or can be adjusted based on a signal metric. The phase adjusted diversity signals can be summed in a signal combiner. The summed signal can be processed as a single receive signal using a single filter and baseband processor.

Abstract: Linear wide dynamic range variable gain amplifiers can be configured using a variable gain amplifier having an abbreviated gain control range in combination with a discrete attenuator controlled to select an attenuation from a predetermined set of attenuation values. The variable gain amplifier is configured to provide substantially linear gain control over the abbreviated gain control range, where the abbreviated gain control range is less than a total desired gain control range. The difference between adjacent attenuation values in the set of attenuation values is configured to be approximately less than or equal to the abbreviated gain control range.

Abstract: Methods and apparatus for calibrating In-phase and Quadrature imbalance within a receiver are described. A calibration process can inject a calibration tone to an RF or IF portion of a receiver. The receiver can frequency translate the tone to distinct I and Q calibration signals. The receiver upconverts the I and Q calibration signals to complementary sidebands or images using distinct and substantially matched upconverters. The complementary sidebands are mixed together to generate an error signal. The receiver determines a phase and amplitude correction based on the error signal.

Abstract: Linear wide dynamic range variable gain amplifiers can be configured using a variable gain amplifier having an abbreviated gain control range in combination with a discrete attenuator controlled to select an attenuation from a predetermined set of attenuation values. The variable gain amplifier is configured to provide substantially linear gain control over the abbreviated gain control range, where the abbreviated gain control range is less than a total desired gain control range. The difference between adjacent attenuation values in the set of attenuation values is configured to be approximately less than or equal to the abbreviated gain control range.

Abstract: Receiver architectures and methods of processing harmonic rich input signals employing harmonic suppression mixers are disclosed herein. The disclosed receivers, mixers, and methods enable a receiver to achieve the advantages of switching mixers while greatly reducing the mixer response to the undesired harmonics. A harmonic mixer can include a plurality of mixers coupled to an input signal. A plurality of phases of a local oscillator signal can be generated from a single local oscillator output. Each of the phases can be used to drive an input of one of the mixers. The mixer outputs can be combined to generate a frequency converted output that has harmonic rejection.

Abstract: A receiver can be configured to include an RF front end that is configured to downconvert a received signal to a baseband signal or a low Intermediate Frequency (IF) signal. The receiver can downconvert the desired signal from an RF frequency in the presence of numerous interference sources to a baseband or low IF signal for filtering and channel selection. The filtered baseband or low IF signal can be converted to a digital representation. The digital representation of the signal can be upconverted in the digital domain to a programmable IF frequency. The digital IF signal can be converted to an analog IF signal that can be processed by legacy hardware.

Abstract: A receiver configured to selectively receive an RF signal from an operating band having a plurality of RF channels. The receiver is configured to upconvert the desired RF channel to an intermediate frequency (IF) greater than the RF channel frequencies. The upconverted RF channel is downconverted to baseband or a low IF. The receiver can perform channel selection by filtering the baseband or low IF signal. The baseband or low IF signal can be upconverted to a programmable output IF.

Abstract: A DC offset removal method and apparatus for use with a receiver, such as a direct conversion receiver. The DC offset error can be upconverted to an intermediate frequency where it appears as a DC offset spurious signal. The DC offset spurious signal can be amplified and downconverted back to a DC signal. The DC signal can be used to determine an offset correction value that can be coupled to a signal path to substantially remove the DC offset error. An embodiment is disclosed that allows a single module to be used to remove the static and dynamic DC offset error components. Another embodiment includes separate portions for the removal of static and dynamic offset errors.

Abstract: A dual conversion receiver architecture that converts a radio frequency signal to produce a programmable intermediate frequency whose channel bandwidth and frequency can be changed using variable low-pass filtering to accommodate multiple standards for television and other wireless standards. The dual conversion receiver uses a two stage frequency translation and continual DC offset removal. The dual conversion receiver can be completely implemented on an integrated circuit with no external adjustments.