Wave on digital oscilloscope

How Does an Oscilloscope Measure Frequency?

Published: 8th July 2021

Oscilloscopes measure the voltage of an electrical signal, which is then graphically represented by waveforms. However, an oscilloscope can be used to take measurements for a number of different applications – one of which is frequency. But how does an oscilloscope measure frequency, exactly? Well, there’s a straightforward answer, and then there’s a slightly more complicated answer.

On most, if not all, modern digital oscilloscopes the calculation is done for you, so you’ll be able to get a frequency reading whilst you’re measuring voltage. Simply press a couple of buttons to see the frequency of the signal you’re trying to inspect, as well as other statistics such as standard deviation and the mean frequency. However, there are ways to work out the frequency without the aid of technology.

How to Calculate Frequency

You can measure time and frequency quite easily using the horizontal scale on your oscilloscope. If you want to ensure accuracy when taking a frequency measurement, it helps to increase the signal area on your oscilloscope display – making it bigger so you can more easily translate the waveform.

Firstly, you need to measure the time using the horizontal scale on your oscilloscope, as well as counting the number of horizontal divisions from one end of the wave to the other where it crosses the Centre Horizontal Graticule Line. Then you can multiply the number of horizontal divisions by the time/division to find the signal’s period. Once you have this, you can perform the frequency calculation: one divided by the period. Mathematically this can be represented as frequency=1/period.

Automatic Measurements on a Digital Scope

As previously mentioned, most high-quality digital oscilloscopes will take measurements automatically, meaning that you don’t have to do the calculations. On Tektronix oscilloscopes, you can find the time measurements under the ‘measurements’ badge on the display. This will give you an accurate, live reading of the frequency, which will change depending on the signal being transmitted.

You can also access all statistic data. This way you can see the standard deviation, mean, maximum, and minimum of the frequency, providing a better idea of how the signal is reacting.

MCS Test are the approved UK partner for Tektronix
Content Source: How Does an Oscilloscope Measure Frequency? | Tektronix


Tektronix DSA8300 Digital Serial Analyser Oscilloscope

This product has been discontinued. Please see the Tektronix Sampling Oscilloscope.

The DSA8300 Digital Sampling Oscilloscope is a complete high-speed PHY Layer testing platform for data communications from 155 Mb/sec to 400G PAM4.

Find out more about Tektronix DSA8300 Digital Serial Analyser Oscilloscope

Tektronix TDS3012C 100 MHz Digital Phosphor Oscilloscope

2 Channel, 100 MHz Frequency Range

The TDS3012C Oscilloscope Series provides you with the performance to visualize fast-changing signals in a compact, battery-capable design.

Find out more about Tektronix TDS3012C 100 MHz Digital Phosphor Oscilloscope

Tektronix TBS2204B 200 MHz Digital Storage Oscilloscope

Frequency Range: 200 MHz
Analog Channels: 4

Shipping: Normally in Stock / Short Lead Time

The TBS2000B Series of Oscilloscopes with a 9-inch WVGA display, 5 million point record length and 2 GS/s sample rate, capture and display significantly more signal to help you debug and validate the designs faster.

Find out more about Tektronix TBS2204B 200 MHz Digital Storage Oscilloscope

Tektronix MSO70604C 6 GHz Mixed Signal Oscilloscope

Frequency Range: 6 GHz
4 Analog Channels, 16 Digital Channels

The MSO70604C is one of the most advanced oscilloscopes in its class—enabling today's engineer to see signals better with minimal noise, debug signal anomalies faster and utilize measurement and analysis tools for automated compliance testing and other verifications.

Find out more about Tektronix MSO70604C 6 GHz Mixed Signal Oscilloscope

You Might also like

EMI Emissions Turntables

A 3-Step Process to Identify Electromagnetic Interference (EMI)

Radiated emissions, most often referred to as electromagnetic interference (EMI), are carefully regulated to ensure reliable operation and safety for users of electrical and electronic equipment.

Read more
4200 Kiethley

How to Measure a MOSFET I-V Curve

One of the best ways to ensure a MOSFET is functioning properly and meets specifications is to determine its characteristics by tracing I-V curves. There are a number of output characteristics requiring I-V tests; you can derive gate leakage, breakdown voltage, threshold voltage, transfer characteristics, and drain current all by simply tracing I-V characteristics and verifying the device is working as it should.

Read more
DPO7 OE1 Tek RT 129 500px

MSO/DPO70000 & DPO70000SX are now Available with Enhanced Capabilities & Features Included as Standard

Tektronix class leading High Performance Oscilloscopes are now available with enhanced capabilities and features included as standard. Tektronix DPO/ MSO 12.5GHZ – 33GHZ C, DX and SX models come with additional enhancements at no additional cost when purchasing a new instrument.

Read more

Sign up for the MCS Newsletter

You will receive all the latest test & measurement news and rental offers.