RF Measurements:Principles & Demonstration

Course 135

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This 5-day lecture-based course explains essential RF measurements that must be made on modern wireless communications equipment - mobile/smart phones, wireless LANs, GPS navigation systems, and others. Functional block diagrams of the essential test instruments will be explained and demonstrated, including vector network analyzers, power meters, spectrum analyzers, digitally modulated signal generators and vector signal analyzers.

Measurements will be demonstrated on actual RF wireless components including power amps, LNAs, mixers, upconverters, and filters. These measurements will include traditional tests of power, gain, group delay, S parameters, AM to PM, intermodulation products, harmonics and noise figure. The unique measurements of wireless communications will then be made with PSK and FSK digitally modulated signals including spectral regrowth, constellation diagram distortion, error vector magnitude (EVM), and bit error rate.

Learning objectives

Upon completing the course you will be able to:

  • understand the unique measurement challenges that become significant as circuit operating frequencies increase.
  • describe the RF measurements that must be made on modern wireless communication equipment.
  • make an association between controls on the front of the instrument and which components they affect inside the box, along with related performance tradeoffs.
  • take proper care of RF cables and connectors in the lab
  • explain why the various measurements must be made.
  • operate the RF test equipment that is used to make these measurements
  • setup and calibrate a Vector Network Analyzer measurement
  • make measurements on power amps, LNA's, mixers, upconverters and filters
  • make traditional tests of power, gain, group delay, S parameters, AM to PM, intermodulation products, harmonics, and noise figure with CW signals.
  • ensure that distortion products from the instrumentation are not corrupting the measurement results
  • make measurements with PSK and FSK digitally modulated signals of spectral regrowth, constellation diagram distortion and ISI, error vector magnitude, and bit error rate.
  • develop reasonable expectations for measurement uncertainties.

Target Audience

Design and production engineers and technicians interested in improving measurement skills through a practical approach will benefit from this course. The lecture includes a review of wireless communication systems, RF components and the tests that must be made, making this an ideal course for professionals wishing to have a thorough grounding in the knowledge of how wireless systems operate. The main demographic among students has been those who are "new to RF," as well as many experienced RF professionals looking for a "refresher" or who have never had the various concepts tied together in a comprehensive way have also greatly benefitted from attending.


Day One

Course Objectives and Course Outline
 • Review of RF principles • Wave parameters - frequency, amplitude, phase • basics of propagation • dB and dBm • Mismatches • Conversion between mismatch expressions - Reflection coefficient, return loss, mismatch loss, SWR • The Smith Chart - an overview • S-parameters
RF Test Equipment - Principles of Operation
 • Cable and connector types/proper care • Signal generators • Power meters and power sensors • Frequency counter • Vector network analyzer • Demonstration: how to setup and calibrate a basic VNA measurement • Vector network analyzer measurements on non-packaged devices

Day Two

 • Spectrum analyzer • Demonstration: how to operate a spectrum analyzer - Resolution Bandwidth, Video Bandwidth, Attenuation, Scaling • Noise figure meter • Vector signal analyzer
Measurement Uncertainties
 • Mismatch uncertainty • VNA - motivation for measurement calibration
RF Communication system block diagram
 • Specifications of components to be tested
Transmitter components
Phase locked oscillator
 • principles of operation • measurement of phase noise - log/video vs. rms averaging on Spectrum Analyzer - Marker noise function
 • Modulation basics • principles of operation • demonstration: measurement of conversion gain using a spectrum analyzer - output spectrum of upconverter

Day Three

Power Amplifier
 • principles of operation • demonstration measurement - swept gain - power sweep/1 dB compression point - AM to PM distortion - phase on the Vector Network Analyzer • Harmonic power using Spectrum Analyzer • checking for distortion products in the test equipment
Receiver Components
Noise and Noise Figure
 • Noise figure measurement • demonstration measurement using Y-factor technique
 • Principles of operation • Demonstration measurement - passband - inband loss - match - group delay on the Vector Network Analyzer

Day Four

Low Noise Amplifiers
 • principles of operation • Noise figure • intermodulation products • demonstration measurement - gain/1dB compression point - output power - phase using power sweep on Vector Network Analyzer • demonstration measurement - S-parameters vs. frequency on the Vector Network Analyzer
 • principles of operation - conversion gain - output power
Intermodulation Products
 • description of intermodulation products • Demonstration: IP3/TOI using a spectrum analyzer • definition of IP2
Overall Receiver Performance
 • Typical overall receiver performance • Calculating system performance

Day Five

Multiple Access Techniques
Performance of RF components with digital signals
 • Block diagram • Digital modulation fundamentals • demonstration measurement - Adjacent Channel Power (ACP) performance vs. power amplifier nonlinearity with different modulation techniques • zero span function on Spectrum Analyzer
Vector Signal Analyzer Modulation Quality Measurements
 • Principles of operation • EVM/Distortion of digital signal due to power amplifier nonlinearity • EVM/Distortion of digital signal due to IF filter group delay • EVM/Distortion due to LO phase noise with mixer • Troubleshooting digital modulation with a Vector Signal Analyzer
Description of Bit Error Rate (BER)
 • RF Communication System Operation