Abstract: An improved complex-IF digital receiver has various improvements. The improved complex-IF digital receiver, for single or dual band applications, preferably synchronizes all of the signals to each other, which may be an integer multiple of each other. For example, the decimation filter, delta-sigma modulator, sensitivity DAC, and other circuits in the receiver can be synchronized. The delta-sigma modulator preferably includes a comparator whose input is coupled to a sensitivity DAC or synchronous dithering circuit. Ideally, the sensitivity DAC forces the comparator to trigger at every clock cycle and reduces the effect of hysteresis and offset at the input of the comparator. The receiver includes a translation circuit that translates an intermediate frequency signal to baseband, where the translation circuit preferably operates a translation ratio that is a multiple of 4.
Type:
Grant
Filed:
September 20, 2002
Date of Patent:
February 6, 2007
Assignee:
DiTrans IP, Inc.
Inventors:
Wesley K. Masenten, Keith Soo Hoo, Peter Stubberud, Thang Victor Dinh, Elias Dagher
Abstract: An improved calibration system for a receiver is configured to calibrate the I and Q paths to correct for gain mismatch and quadrature phase errors. In a preferred embodiment, the calibration system calibrates the I and Q paths by using a calibration signal and a reference signal coherently generated from the same single frequency source. The calibration signal is input into the receiver and propagated along the I and Q paths of the receiver simultaneously with a received signal. The reference signal coherently extracts the calibration signal from the I and Q paths. The resulting calibration signals include a component at zero frequency that can be used to measure the phase and gain error. The calibration system is configured to adaptively calibrate the gain and phase error by iteratively measuring the gain and phase error and reducing it to the desired level or eliminating it altogether.
Type:
Grant
Filed:
January 31, 2003
Date of Patent:
December 5, 2006
Assignee:
DiTrans IP, Inc.
Inventors:
Wesley K. Masenten, Peggy L. Escobedo, Chinghsiu Shih, Erik C. Fountain, Robert A. Dell-Imagine
Abstract: A receiver is adaptively calibrated by using a coherent reference signal. The reference signal is selected to be offset from a center frequency of the calibration signal such that the resultant product is offset from baseband by some small amount. The resultant product is used to determine a next value of the calibration parameters.
Abstract: An adaptive antenna is implemented using a plurality of modular array element modules. Each array element module comprises an antenna element of the adaptive antenna. Each antenna element is coupled to a weighting circuit is also coupled to a previous weighting circuit within a previous array element module in a concatenated manner. Each weighting circuit is configured to apply a complex weight to the antenna samples and add the result to the output of the previous weighting circuit. Each antenna element is also coupled to a cross-correlation measurement circuit configured to cross-correlate antenna samples with adaptation error samples to provide cross-correlation measurement samples to a controller which determines a weight applied by the weighting circuit.
Type:
Grant
Filed:
October 11, 1999
Date of Patent:
November 23, 2004
Assignee:
Ditrans IP, Inc.
Inventors:
Wesley K. Masenten, Robert A. Dell-Imagine