Logitech Europe S.a.

Qualcomm Incorporated

Logitech, Inc.

Peter A Thompson

Bryed L Billerbeck

Thomas C Lyon

Chaekwan Lee

Kyung Sup Han

Bill Xenakis

An embodiment of the present invention includes a technique to calibrate receiver and transmitter in a communication system. N digitized samples I(n) and Q(n) are stored. The N digitized samples represent in-phase and quadrature (I-Q) components, respectively, of a down-converted signal from a receiver. The I-Q components are generated from a quadrature demodulator or modulator having I-Q imbalance. Phase and gain adjustment constants are computed from the N digitized samples to compensate for the I-Q imbalance using a closed form solution. Another embodiment of the present invention includes a technique to calibrate a transceiver in a communication system without using a calibrated reference receiver. A first test signal at a first frequency is injected to a transmitter having a quadrature modulator with I-Q imbalance. The quadrature modulator has a carrier frequency. The transmitter generates a transmitter signal. The transmitter signal is detected to generate a composite signal having the first test signal and a second test signal at a second frequency twice the first frequency. The composite signal is digitized. I-Q direct current (DC) offset, phase, and gain corrections are computed from the digitized composite signal to correct the I-Q imbalance using a closed form solution.

Fast in-phase and quadrature imbalance calibration

A system and method providing dynamic detection and correction of data corrupted by external interference in wireless communications network includes an interference detection unit and correction unit. Detection unit detects impact on video signals based on measuring condition of predetermined portion of video signals. Correction unit corrects the interference by selecting previously stored data to replace corrupted video data.

Dynamic radio frequency interference detection and correction

A system which marries a tethered, digital bus with image broadcasting to allow multiple, low-cost cameras to communicate with a host. This is done by using an external receiver on a tethered bus, and by putting much of the processing circuitry in the receiver, rather than the camera. The broadcasting can be either a NTSC/PAL type of analog broadcasting or a digital broadcasting technique. The camera can be made with low cost, readily available NTSC/PAL, other analog video components, or with readily available digital telephone components. The external receiver unit of the present invention does all the necessary data processing and compression to fit the available bandwidth of the bus to which it is communicating, and provides for a low cost and extensible method of inputting digital image data into a personal computer (PC) or other host.

Wireless intelligent host imaging, audio and data receiver

A system and method is disclosed for compressing and decompressing composite video signals. In one type of operation a composite video signal (e.g., an NTSC signal) is sampled and the samples compressed into 3 or 5 bit composite values, depending on the system mode (PREVIEW or HIGHRES). For the HIGHRES mode the compressed composite values are written into a RAM for at least the four fields associated with the most recent two frames. As needed, the compressed values are transferred to a decoding engine implemented in software. The decoding engine, without any need for phase locked loop circuitry, decompresses the data, and decodes the decompressed digital composite values into YUV and/or RGB values. When the system is in the 5-bit mode, the decoding engine scans and compares all four fields to detect the existence of motion in the image, which could blur the captured image. In regions with motion only a single field of data is used as the source of the image data for those regions. In regions with no motion the information from all four fields is used to reconstruct the image. When the system is in the 3-bit mode, data from only a single field is used to generate the entire captured or displayed image. Also disclosed is a system and method for converting digital video data to composite video signals.

Growing community of inventors

Millbrae, CA, United States of America

Peter A Thompson