Preselector Tune Out Accuracy Performance Test

This test verifies that the PSA preselector tune out voltage is operational. The 11974 Series External Mixers require a tune voltage of (1.5 volts/GHz x LO Freq) to tune their internal preselector. If the PSA 1st LO is tuned to 3 GHz the preselector tune voltage should be 4.5 volts. Similarly, for an LO frequency of 6.6 GHz the tune voltage should be 9.9 volts. The Pre-sel Tune Out voltage is listed as a nominal (Non-Warranted) parameter so the test limit will be set at +/- 10%.

To verify the tune voltage, the PSA is be placed in external mixing mode using a harmonic number of -10. The PSA frequency offset is set to 321.4 MHz so that the PSA center frequency is exactly 10 times the 1st LO frequency. A DVM is connected to the PRE-SEL TUNE OUT port and the tune voltage is monitored while the PSA is tuned from 30 GHz to 66 GHz. The resulting LO frequency is 3.0 GHz to 6.6 GHz. The measured tune voltage will be compared to a test limit of (1.5 volts/GHz x LO Freq) +/- 10%.

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Required Test Equipment

Connection Setup