Patent ID: 9252895
Filing Date: 2016-02-02
CPC Classification: H03D,H04B

Claim Text:
1. A system for measuring a full spectrum of a modulated output signal provided by a device under test (DUT), the system comprising: a signal generator configured to generate a modulated input signal having a modulation repetition rate, and to generate a trigger signal synchronous with a sub-harmonic of the modulation repetition rate; an up-converter configured to up-convert the modulated input signal to a radio frequency (RF) stimulus signal provided to the DUT, wherein the DUT outputs the modulated output signal in response to the RF stimulus signal, the modulated output signal having the same modulation repetition rate as the modulated input signal; a receiver having an intermediate frequency (IF) bandwidth less than a total bandwidth of the modulated output signal, the receiver comprising: a harmonic phase reference (HPR) generator configured to generate a repetitive HPR signal having an HPR bandwidth wider than or substantially equal to the total bandwidth of the modulated output signal, wherein the reference mixer is configured to consecutively mix the HPR signal from the HPR generator with the plurality of LO signals to provide HPR IF signals input to a reference channel of the ADC, and the first mixer is configured to consecutively mix the modulated output signal from the DUT with the plurality of LO signals to provide first IF signals corresponding to the HPR IF signals and input to a first channel of the ADC, the HPR IF signals and the corresponding first IF signals forming ADC data records, respectively, and wherein the number of different LO frequencies of the LO signals is selected to provide enough ADC data records to capture the full spectrum corresponding to the total bandwidth of the modulated output signal from the DUT.