Analog Devices,inc.

Analog Devices Global

Analog Devices International Unlimited Company

Martin McCormick

Patrick Joseph Pratt

David J McLaurin

David J Mclaurin

Peadar Antony Forbes

Qingdong Meng

Raju Hormis

Hajime Shibata

Antonio J Montalvo

Christopher Mayer

Jeffrey G Bernstein

Richard E Schreier

Wenhua William Yang

Benjamin Vigoda

Jialin Zhao

Yunzhi Dong

Donald W Paterson

Manish J Manglani

Jose Barreiro Silva

Steven R Bal

Chris Angell

Theophane Weber

A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. The QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Wideband quadrature error detection and correction

Transmitter noise cancellation may be applied on a channel by channel basis to active channels of an incoming radio frequency signal received at a receiver. A noise cancellation filter may be provided for each active channel in a predetermined signal band. Applying noise cancellation on a per active channel basis instead of to the entire receive band may substantially reduce the filtering requirement and number of filter coefficients or taps to save power and reduce manufacturing costs. Channelized transmitter noise cancellers, multi transmitter-receiver cross coupling cancellers, and hybrid full signal band and channelized transmitter noise cancellers are also provided.

Radio frequency transmitter noise cancellation

For continuous-time multi-stage noise shaping analog-to-digital converters (CT MASH ADCs), quantization noise cancellation often requires accurate estimation of transfer functions, e.g., a noise transfer function of the front end modulator and a signal transfer function of the back end modulator. To provide quantization noise cancellation, digital quantization noise cancellation filters adaptively tracks transfer function variations due to integrator gain errors, flash-to-DAC timing errors, as well as the inter-stage gain and timing errors. Tracking the transfer functions is performed through the direct cross-correlation between the injected maximum length linear feedback shift registers (LFSR) sequence and modulator outputs and then corrects these non-ideal effects by accurately modeling the transfer functions with programmable finite impulse response (PFIR) filters.

Adaptive digital quantization noise cancellation filters for mash ADCs

Apparatus and methods for transceiver calibration are provided. In certain configurations, a transceiver includes a transmit channel and an observation channel. The transmit channel includes a transmit mixer that up-converts a transmit signal by a first or transmit local oscillator frequency. The observation channel includes an observation mixer that down-converts an observed signal from the transmit channel by a second or observation local oscillator frequency that is offset from the first local oscillator frequency. By observing the transmit channel using a local oscillator frequency that is offset relative to the transmit channel's local oscillator frequency, the observation channel can observe transmit channel impairments substantially independently from observation channel impairments.

Apparatus and methods for transceiver calibration

For small cells, transceivers demand high performance while maintaining system efficiency. The present disclosure describes a highly integrated cellular transceiver that offers such features by providing one or more digital functions on-chip, onto the same die in the cellular transceiver. Effectively, the scope and boundary of the cellular transceiver is expanded to move beyond the data converters of the transceiver to include a variety of digital functions, thus integrating more of the signal chain in the cellular transceiver. Integration can greatly reduce complexity for the baseband processing, lower the cost of the overall transceiver system, reduce power consumption, and at the same time, benefit from improvements on the digital functions through integration.

Highly integrated radio frequency transceiver

An approach to linearization relaxes the requirements on the digitization of the analog output signal while maintaining the benefits of a high sampling rate of the output signal. The digitization approach extracts sufficient information to characterize the output signal over a wide bandwidth without necessarily determining sufficient information to fully represent the output signal, for example, without sampling the output signal at the Nyquist sampling rate with a sufficient precision to accurately represent the signal.

Relaxed digitization system linearization

An approach to signal conversion adapts the signal conversion process, for example, by adapting or configuring signal conversion circuitry, according to inferred characteristics (e.g., probability distribution of value) of a signal being converted. As an example, an analog-to-digital converter (ADC) may be adapted so that its accuracy varies across the range of possible input signal values in such a way that on average the digital signal provides a higher accuracy than had the accuracy remained fixed. In another example, models (and corresponding inference circuitry) of both an input signal process and of a quantization process are used to improve signal conversion accuracy.

Signal conversion

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Cambridge, MA, United States of America

Martin McCormick