Microtune (texas), Inc.

Csr Technology Inc.

Zoran Corporation

Carey Ritchey

Kim E Beumer

Marius Pop

Tom L Davis

Jan-Michael Stevenson

R William Ezell

Jose L Esquivel

An agile RF tuner circuit capable of converting a wide portion of RF signal into an IF signal suitable for analog-to-digital conversion. The circuit up converts a received RF signal to a high IF signal and then down converts the high IF signal to a low IF signal. Embodiments of the RF circuit incorporate harmonic reject mixers to suppress harmonics and intermodulations typically associated with the frequency conversion process.

Broadband tuner for very wide signal conversion

An agile RF tuner circuit capable of converting a wide portion of RF signal into an IF signal suitable for analog-to-digital conversion. The circuit up converts a received RF signal to a high IF signal and then down converts the high IF signal to a low IF signal. Embodiments of the RF circuit incorporate harmonic reject mixers to suppress harmonies and intermodulations typically associated with the frequency conversion process.

A system for providing automatic gain control (AGC) comprises a signal path with an RF input, a plurality of power detectors in communication with the signal path, each of the power detectors operable to measure a total broadband power level of a signal in the signal path, each of the power detectors positioned to monitor a point in the signal path corresponding to a change in signal bandwidth, a control system operable to receive from each of the power detectors information associated with the power level and to adjust attenuation in the signal path in response to the information to achieve desired gain control.

AGC system and method for broadband tuners

Linearizer circuitry is disclosed for providing control signal outputs to operate a controllable attenuator throughout a relatively large dynamic range while maintaining a relatively consistent return loss. Preferred embodiment linearizer circuitry provides a series control current and a shunt control current for coupling to a PIN diode attenuator, such as may be configured in a &#x3c0; network or a T network. Preferably, differential pairs are utilized in providing each of the control current outputs.

Linearizer for a PIN diode attenuator

Diode network configurations are disclosed in which cathode bias voltage is held substantially constant to provide an attenuator circuit in which return loss is optimized throughout a broad dynamic attenuation range. Preferred embodiments include PIN diodes arranged in a &#x3c0; network having two attenuation control signals provided thereto. Alternative embodiments include PIN diodes arranged in a T network having two attenuation control signals provided thereto.

Broadband PIN diode attenuator bias network

Disclosed are systems and methods which provide signal processing circuitry utilizing a variable gain transimpedance amplifier configuration which is economical to implement and which provides for power efficient circuit implementation. Preferred embodiments provide a transimpedance amplifier having an output intercept that remains constant while a corresponding input intercept increases as gain is reduced. An analog optical receiver preferably implements an architecture in which the variable gain transimpedance amplifier is disposed as an input amplifier.

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Murphy, TX, United States of America

Carey Ritchey