US 11,057,125 B1Granted

Programmable digital loopback for RF applications

AssigneeAnalog Devices, Inc.

InventorsPeter Delos, Carroll C. Speir

Life of this patent

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Abstract

Various approaches to implementing digital loopback in a radio frequency (RF) system are disclosed. An example RF system includes a receiver that includes an ADC and a transmitter that includes a DAC. The apparatus includes multiple digital loopback circuits provided at different points between the digital domain processing of the receiver and the transmitter. Each digital loopback circuit may include a combiner and one or more weighing circuits, which make the circuit programmable. The combiner of a given digital loopback circuit is configured to combine a RX signal and a TX signal at a particular point of the digital domain processing of the receiver and the transmitter where said digital loopback circuit is implemented. The one or more weighting circuits are configured to define the how much of the TX signal and/or RX signal is used for said combination.

Claims28

Dependent claims

An apparatus for implementing digital loopback for a radio frequency (RF) system, the apparatus comprising:

a receiver, comprising an analog-to-digital converter (ADC) and a first receive (RX) processing unit;
a transmitter, comprising a digital-to-analog (DAC) and a first transmit (TX) processing unit;
a first loopback circuit, comprising a first loopback path, a first combiner, and a first TX weighting circuit, wherein:
the first loopback path is configured to provide a signal indicative of an output of the ADC to the first combiner,
the first TX weighting circuit is configured to apply a first TX weight to an output of the first TX processing unit to generate a weighted output of the first TX processing unit, and
the first combiner is configured to combine a first RX signal and a first TX signal to generate a first combined signal to be provided to the DAC, where the first RX signal is a signal indicative of the output of the ADC, and the first TX signal is a signal indicative of the weighted output of the first TX processing unit;
and
a second loopback circuit, comprising a second loopback path, a second combiner, and a second TX weighting circuit, wherein:
the second loopback path is configured to provide a signal indicative of an output of the first RX processing unit to the second combiner,
the second TX weighting circuit is configured to apply a second TX weight to a signal indicative of an input signal to generate a weighted input for the first TX processing unit,
the second combiner is configured to combine a second RX signal and a second TX signal to generate a second combined signal to be provided to the first TX processing unit, where the second RX signal is a signal indicative of the output of the first RX processing unit and the second TX signal is a signal indicative of the weighted input for the first TX processing unit, and
the first TX processing unit is configured to generate the output of the first TX processing unit based on the second combined signal.

9 more elements

A method of operating a radio frequency (RF) system for implementing digital loopback, the system including an analog-to-digital converter (ADC), a first receive (RX) processing unit, the method comprising:

applying a first TX weight to an output of the first TX processing unit to generate a weighted output of the first TX processing unit;
combining a first RX signal and a first TX signal to generate a first combined signal to be provided to the DAC, where the first RX signal is a signal indicative of an output of the ADC, and the first TX signal is a signal indicative of the weighted output of the first TX processing unit;
applying a second TX weight to a signal indicative of an input signal to generate a weighted input for the first TX processing unit;
combining a second RX signal and a second TX signal to generate a second combined signal to be provided to the first TX processing unit, where the second RX signal is a signal indicative of an output of the first RX processing unit, and the second TX signal is a signal indicative of the weighted input for the first TX processing unit;
and
generating the output of the first TX processing unit based on the second combined signal.

3 more elements

An apparatus for implementing digital loopback for a radio frequency (RF) system, the apparatus comprising:

a circuit for applying a first transmit (TX) weight to an output of a first TX processing unit to generate a weighted output of the first TX processing unit;
a circuit for combining a first receive (RX) signal and a first TX signal to generate a first combined signal to be provided to a digital-to-analog (DAC), where the first RX signal is a signal indicative of an output of an analog-to-digital converter (ADC), and the first TX signal is a signal indicative of the weighted output of the first TX processing unit;
a circuit for applying a second TX weight to a signal indicative of an input signal to generate a weighted input for the first TX processing unit;
and
a circuit for combining a second RX signal and a second TX signal to generate a second combined signal to be provided to the first TX processing unit, where the second RX signal is a signal indicative of an output of a first RX processing unit, and the second TX signal is a signal indicative of the weighted input for the first TX processing unit,
wherein the output of the first TX processing unit is based on the second combined signal.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/912,524Filed 25 Jun 2020
Granted: 6 Jul 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H04B 1/0028
Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or…
H04B 17/14
For calibration: of the whole transmission and reception path, e.g. self-test loop-back
H04B 1/0007
Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or…
H04B 1/40
Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of…: circuits