Nelson-Ross PSA-011

The Nelson-Ross PSA-011 is a spectrum analyzer plug-in for 500-series scopes. The center frequency range is 10 Hz to 20 kHz. It can display amplitude in linear or log scale.

The input is high-impedance and is AC-coupled. The PSA-011 is a single-conversion architecture with a pair of 6BH6 tubes serving as a balanced mixer. After IF filtering and amplification, the signal is detected using a 1N34A germanium diode. The detected voltage from the diode directly drives pin 3 of the scope plug-in interface connector. Pin 1 of the scope plug-in interface connector (the other side of the differential input) is fed a DC vertical position voltage by the PSA-011.

The voltage-controlled local oscillator is tuned using a variable-reactance tube, V6, a 6201.

• Manual for Nelson-Ross 001, 002, 003, 011, 012, and 013 (PDF)

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