US 6,211,663 B1 · Baseband time-domain waveform measurement method

Abstract

A time-domain baseband measurement method measures modulated microwave signals typically used in communication systems by converting microwave signals to baseband before measurement for improved accuracy compared to direct measurement at the microwave frequency. A downconverting receiver is first characterized using a prior characterization method and then the modulated microwave signal is applied to the downconverting receiver and the response of the downconverting receiver is removed to provide an accurate characterization of the modulated microwave signal. Such an accurate measurement of the modulated microwave signal can be used for communications system performance verification as well as for characterizing communications devices and systems. One particular application is the measurement of input/output characteristics of nonlinear power amplifiers using such modulated microwave signals.

Claims16

Dependent claims

A method of determining a low pass equivalent of an input signal, the method comprising the steps of,

determining a downconverter frequency response for a downconverting frequency translation device,
receiving the input signal by the downconverting frequency translation device,
downconverting the input signal into a baseband signal by the downconverting frequency translation device,
measuring the baseband signal, and
calculating the low pass equivalent of the input signal by analytically removing the downconverter frequency response from the baseband signal.

2 more elements

A method of determining the frequency response of a device under test, the method comprising the steps of,

receiving a microwave test signal by a downconverting frequency translation device,
downconverting the microwave test signal into a test baseband signal by the downconverting frequency translation device,
measuring the test baseband signal,
exciting the device under test with the microwave test signal to produce a microwave response signal,
downconverting the microwave response signal into a response baseband signal by the downconverting frequency translation device,
measuring the response baseband signal, and
calculating the frequency response of the device under test by dividing a Fourier transform of the response baseband signal by a Fourier transform of the test baseband signal.

4 more elements

Dependencies are inferred from the claim text.

Baseband time-domain waveform measurement method

Life of this patent

Baseband time-domain waveform measurement method

Life of this patent

Abstract

Claims16