Rf Magic, Inc.

Conexant Systems, Inc.

Entropic Communications, Inc.

Bert L Fransis

Keith Bargroff

Raducu Lazarescu

Peter J Shah

Keith J Rampmeier

John Francis O'Connor

Kostas Papathanasiou

Esa Tarvainen

Tony Mellissonos

Donghai Wang

Carl R C De Ranter

Tony Mellissinos

Kosta Papathanasiou

Keith P Bargroff

A broadband tuner includes a tracking filter with calibration to compensate for component errors and drift. The filters use off-die inductors that are preferably within a system-in-package (SIP) with other critical tuner components, which produces a highly integrated tuner front end with high Q filters within a single package. High voltage varactors with a large tuning range can be used for variable capacitors. The integration of the tuner into a SIP allows the tuner design to be optimized for cost and performance while keeping the critical RF layout requirements within the tuner. A configurable tuner front end enables modes for low noise, high linearity, good input return loss (S) across the entire RF band, and applying a test tone in the calibration mode. The switchable mode enables the tuner to be effective during weak terrestrial reception, strong terrestrial reception, and connection to a cable plant.

Receiver with tuner front end using tracking filters and calibration

An N&#xd7;M crosspoint switch allows a signal from any one of the N inputs to be routed to one or more of the M crosspoint switch outputs. The switches within the crosspoint switch can be configured as voltage mode or current mode switches. In voltage mode switching an input to the crosspoint switch is provided to an input device, such as an amplifier, having a low output impedance. The output of the low impedance device is provided to a switch that connects the output of the low impedance device to a high input impedance device, such as a band translation device. In current mode switching, the low impedance output of the input device is connected to selectively activated high isolation transconductance devices having high input impedances. The outputs of the transconductance devices are connected to low impedance devices that operate as summing nodes.

NxM crosspoint switch with band translation

A VCO control circuit includes a variable delay block, a delay counter, and a tuning range selector coupled to one or more tuning circuits, e.g. one or more VCOs, an arrangement of capacitors, varactor diodes, or inductors. The variable delay block receives a reference signal and a delay signal for setting the delay amount applied to the reference signal, and in response outputs a delayed reference signal, whereby two or more different delays may be applied to the reference signal. The delay counter receives the delayed reference signal and an outputs a delay counter output signal in response. The tuning range selector receives the delay counter output signal, and changes the tuning range of the one or more connected tuning circuits in response.

VCO control circuit and method of operation

An oscillator circuit includes a tank circuit, first and second oscillator transistors, and a gain-cell tuning inductor. The tank circuit includes first and second ports, and is configured to resonate at one or more predefined frequencies. The first oscillator transistor includes first port, a second port coupled to the first port of the tank circuit, and a third port. The second oscillator transistor includes a first port, a second port coupled to the second port of the tank circuit, and a third port. The gain-cell tuning inductor is coupled between the third ports of the first and second oscillator transistors and is operable to conduct a biasing signal supplied thereto to the third ports of the first and second oscillator transistors.

Oscillator topology for very low phase noise operation

An LO generation circuit generates an LO signal by doubling and quadrupling the frequency of a VCO signal. The frequency doubling and quadrupling provides high VCO-RF isolation as well as suppression of spurious noise signals in the LO output. The frequency doubler takes a quadrature signal input and utilizes mixer cores having double balanced transistor pairs to provide an output signal having doubled frequency but maintaining the phase balance of the input signal.

Broadband frequency multiplier

An amplifier circuit including a novel degeneration input stage that permits a low Noise Figure and superior linearity to be achieved in combination. The amplifier is suitable for use in fully integrated direct-conversion tuner circuits, and provides continuously variable gain functionality implemented by steering current away from an output load of the amplifier through differential transistor pairs located in the current signal paths of an input stage. Voltage headroom problems are avoided by placing the attenuation resistors of the degenerated input stage in the signal path, such that there is little or no DC voltage drop across the resistors. Further, this arrangement permits very accurate on-chip matching to an off-chip signal source. The distribution of IP,values over the gain range of the amplifier, as well as gain and NF characteristics, are dependent on resistor ratios rather than absolute values. These amplifier characteristics are thus largely temperature and process independent. In one embodiment of the invention, separate voltage supplies, ground connections and bias circuits are provided for different portions of the circuitry in order to improve noise immunity and reduce coupling of an input signal to the output of the amplifier circuit.

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San Diego, CA, United States of America

Bert L Fransis