Two incompatible definitions of noise factor can lead to confusion, which you can alleviate by understanding where the differences lie.
vector network analyzers
How to determine noise figure: part 3
Noise factor and noise figure as defined in an IEEE standard can be derived from a two-port device’s equivalent noise temperature. In part 1 and part 2 of this series we discussed several ways to indicate the noise performance of a device under test (DUT). We first introduced the concept of noise factor based on […]
How to determine noise figure: part 2
The relationship between noise and temperature prompted a precursor of the IEEE to promulgate an alternative definition of noise figure in 1959. In part 1 of this series, we described the work of the Danish-American radio engineer Harald Friis, who described noise factor F of a device or system as the ratio of the input-power […]
How to interpret a QAM display: part 1
A constellation diagram plots a quadrature amplitude modulation (QAM) signal’s in-phase and quadrature components. The EE World article “Should I use a spectrum, signal, or vector network analyzer?” in part 3 mentioned that vector-signal analyzers (VSAs) can display modulation-domain and frequency-domain information. Other instruments incorporating digital signal processing (DSP) capabilities, including oscilloscopes, can provide insights into […]
Should I use a spectrum, signal, or vector network analyzer? part 3
In part 2 of this series, we looked at a swept-tuned spectrum analyzer and how it could sweep a frequency span of interest from 1 MHz to 1.1 MHz with a sweep time of 50 msec. As Figure 1 shows, the analyzer readily identifies a signal at 1.03 MHz but misses the intermittent signals shown […]
Should I use a spectrum, signal, or vector network analyzer? part 1
Signal analysis is invaluable for applications ranging from amplifier characterization to signal intelligence. In a recent series, we discussed specs such as 1-dB compression and third-order intercept points. At the end, I pointed to some application notes that explain how to use specific spectrum, signal, and vector network analyzers to make these measurements. These instruments’ […]
New products at the EMC & Compliance International Conference
At the annual UK event, Tekbox, Y.I.C. Technologies, and Harogic Technologies were among the companies exhibiting new EMC measurement equipment. The EMC & Compliance International conference and training was held again in Newbury, UK, from May 22 to 23 this year (Reference 1). This was my first opportunity to attend this annual conference hosted by […]
IMS 2023 roundup: test equipment
Test equipment plays a major role in product development and production, which was apparent at IMS 2023. In the photos and videos below, you’ll get a taste of test developments at RF, mmWave, and sub-THz frequencies. This year, D-band (110 GHz to 170 GHz) seized a larger portion of the exhibit hall than in past […]
What is de-embedding and how do I perform it (part 1)?
It’s a tenet of the test-and-measurement industry that you should concentrate on looking for defects in your device under test (DUT) — not in your test equipment. Figure 1 illustrates a common problem. An instrument presents an incorrect reading; in this case, an LRC meter or multimeter presents a resistance reading that’s about 5% low. […]
What are insertion loss and return loss and how can I measure them?
These basic RF measurements often uncover system problems in wired and wireless communications. If you observe a signal traveling from a source to a load through a passive system of some sort, you will notice that the signal attenuates by the time it reaches the load, and you will also notice that some of the […]
