Gated sweep in spectrum analyzers
View Patent ↗A measurement technique that provides a full solution to the gated local oscillator sweep measurement and improves the accuracy of signal analyzers in gated sweep mode by pre-sweeping the local oscillator at the beginning of a gate pulse and over-sweeping the local oscillator at the end of each gate pulse.
1. A signal analyzer comprising:
a RF step attenuator, receiving a RF signal, generating an attenuator signal;
a mixer, receiving the attenuator signal and a LO signal, generating a mixer signal;
an IF Resolution Bandwidth Filter, receiving the mixer signal, generating an IF signal;
an IF Log Amplifier, receiving the IF signal, generating an amplifier signal;
an Envelope Detector, receiving the amplifier signal, generating an envelope signal;
a gate controller, receiving the envelope signal and a Ready signal, generating a GC output signal and a GC control signal;
a Video Bandwidth Filter, receiving the GC output signal, generating a video signal;
a Peak Sample Detector receiving the video signal, generating a peak signal;
an A/D Converter receiving the peak signal, generating an A/D signal;
Display logic receiving the A/D signal, generating a Reset signal and a Display signal;
a display receiving the display signal;
a scan generator, bidirectionally connected to the gate controller, receiving the GC control signal and outputting the Ready signal, having an scan signal; and
a local oscillator, receiving the scan signal, generating the LO signal.
2. An apparatus, as in claim 1 , wherein the gate controller is implemented as a FPGA.
3. A method comprising:
for the signal analyzer of claim 1 having a gated sweep mode,
applying a measurement delay to allow local oscillator transients to decay;
applying a gated sweep measurement; and
oversweeping for a predetermined duration.