VIDEO: Audio Reception in Tektronix RSA306 PC-Based Spectrum Analyzer

A Tektronix RSA306 PC-Based Spectrum Analyzer, equipped with a whip antenna, can actually receive FM broadcasts and play the audio through the connected user-supplied PC. We’ll see how to configure the instrument to do this.

Hi and welcome to our 79th Test and Measurement Video. Once again we’re looking at the Tektronix RSA306 PC-Based Spectrum Analyzer. A bench-type spectrum analyzer is far more expensive than an oscilloscope with parallel specifications. This has been an impediment to more widespread use of this specialized frequency-domain instrument. That is unfortunate because the spectrum analyzer, especially in its real-time version, is an enormously powerful and capable engine that performs spectral analysis like therre is no tomorrow.

To confront the price barrier, Tektronix has come out with a PC-based spectrum analyzer that is priced at a fraction of a bench model’s cost.

This is possible because the PC-based spectrum analyzer leverages the enormous computing power of a user-supplied computer with free software available at the manufacturer’s website.

For this demonstration, we’ll focus on a unique feature in the RSA306 Spectrum Analyzer – its ability to tune in an FM broadcast and actually play programing through the connected PC. A bench-type spectrum analyzer could not do this without some added circuitry and a speaker.

Let’s see how this is done:

First, the RSA306 module is cabled to the PC with SignalVu-PC software installed. In this FM demodulation exercise, the demo board is not used. In its place the Tektronix whip antenna is screwed into the module’s RF port.

In the PC with the SignalVu-PC interface displayed, click the Preset button.

In the spectrum display, set the Center Frequency to 97.75 MHz and the Span to 20.5 MHz. Set the Reference Level to -30dBm.

Right click the screen and choose Marker to Peak.

(To right click in a laptop where there is no mouse, tap two fingers simultaneously on the touchpad.) Click To Center in the bottom marker setting area. This sets the center frequency of the spectrum analyzer to the center of the signal.

In the Setup menu, click Audio.

Select FM – 200 kHz as the demodulation.

Click Run to start listening to the FM radio signal.

Adjust the audio gain setting so you can hear the demodulated FM radio signal. The sound level is also affected by the setting of the Windows volume control.

Click the Browse . . . button to select the location where you want to save the file.

Enable the Activate button to start saving the audio, and disable the Activate button when you want to stop saving. The saved audio format is .wav, which can be played by Windows Media Player in your PC.

Here is the RSA306 Spectrum Analyzer tuned to 91.5 MHz center frequency to listen to local broadcasting.

Drag the marker to other spectrum peaks, center the peaks and listen to the programing at other channels.

Thanks for watching. New videos are added periodically, so check back frequently.