---
title: "Spectrum Analyzer Basics | Workbench Wednesdays"
description: "Learn the four basic controls you need to use to make measurements with any spectrum analyzer. You'll also see some advanced measurements as well."
canonical: "https://www.baldengineer.com/spectrum-analyzer-basics.html"
author: "James Lewis"
date: "2019-10-17T02:06:58Z"
lastmod: "2022-03-31T03:54:34Z"
categories: ["blog","element14","measurements","test-equipment","workbench-wednesdays","videos"]
tags: ["electronics-basics","fpc1500","rohde-schwarz","sdr","spectrum-analyzer"]
---

# Spectrum Analyzer Basics | Workbench Wednesdays


A spectrum analyzer displays signals in the frequency domain. To use one, you only need to know about four controls: reference level, center frequency, and resolution bandwidth. In this episode, see how to use a spectrum analyzer and determine the transmitting frequency of a device.

The example device is my microphone transmitter. It operates around 500 MHz with FM modulation. You'll see how I step through the spectrum analyzer controls to find the exact frequency. At the end of the episode, I show some advanced measurements you can do with a modern spectrum analyzer. My favorite one is the demodulation.

Using a "zero span," it is possible for a spec an to demodulate an FM or AM signal. In my case, I used a [HackRF SDR](https://greatscottgadgets.com/hackrf/) to generate an RF signal modulated by a wave file. (You'll have to watch the episode to hear an easter egg!) After the spectrum analyzer down converts and demodulates the signal, it plays the audio through its speaker.

[![spectrum analyzer block diagram](/wp-content/uploads/2019/10/spectrum-analyzer-block-diagram-1024x464.jpg)](/wp-content/uploads/2019/10/spectrum-analyzer-block-diagram-1024x464.jpg)

spectrum analyzer block diagram


The block diagram might look familiar if you know a heterodyne receiver's architecture. The two designs are very similar. The difference is the spec an has a sweep generator that automatically tunes the local oscillator. (I explain in more detail in the video.)

The spec an I used in the episode is my [R&S FPC1500](https://www.rohde-schwarz.com/us/product/fpc-productstartpage_63493-542324.html). You can read my [FPC1500 review here](/fpc1500-review.html). Technically it is a one-port network analyzer, but I only used the spectrum mode in the video.

[See show notes on element14](https://www.element14.com/community/docs/DOC-93509/l/workbench-wednesday-instrument-basics-spectrum-analyzer?ICID=baldengineer)