What Is A Spectrum Analyzer?
A spectrum analyzer is a device that displays signal amplitude (strength) as it varies by signal frequency. The frequency appears on the horizontal axis and the amplitude is displayed on the vertical axis. The primary use of a spectrum analyzer is to measure the power of the spectrum of known and unknown signals. It measures carrier power level, harmonics, spurious, sidebands and phase noise.
Spectrum analyzer is just a receiver which displays the signal fed to its Radio Frequency (RF) input port from any Radio Frequency (RF) transmitting device through cable or with antenna. Modern real time spectrum analyzers even decode and display complex broadband Radio Frequency (RF) signals emitted/acquired using various wireless devices which for example include WLAN, WiMAX, GSM, Zigbee, LTE etc.
Types Of Spectrum Analyzer
- Swept-tuned or superheterodyne
- Fast Fourier Transform (FFT)
- Real-time
- Audio
What You Need To Know About Spectrum Analyzer
- Spectrum analyzer is used to measure signal characteristics e.g carrier power level, harmonics, spurious, sidebands, phase nose etc on unknown signals.
- Spectrum analyzer provides less accuracy in measurement.
- Spectrum analyzer do not have source incorporated. It can demodulate and measure complex signals.
- While doing measurements with spectrum analyzer, it is easy to place a marker on the display, but interpretation of results is difficult.
- Spectrum analyzer uses higher IF bandwidth filters.
- Spectrum analyzer house receivers only with single channel.
- Spectrum analyzer can be used for scalar component measurements only. They are not used for phase measurements.
- Spectrum analyzer does not have advanced error correction feature.
- The RSA3408A from Tektronix is real time spectrum analyzer.
- It uses only frequency sweep for measurement.
What Is Network Analyzer?
A network analyzer is an instrument that measures the network parameters of electrical networks. Network analyzers consist of source and multiple receivers and measures broadband frequency signal using techniques such as power and frequency sweep. Network analyzers are often used to characterize two-port networks such as amplifiers and filters but can be used on networks with an arbitrary number of ports.
Network analyzer provides higher measurement accuracy when compared to spectrum analyzer due to vector error correction feature. Today, network analyzers commonly measure S-parameters, because reflection and transmission of electrical networks are easy to measure at high frequencies.
Types Of Network Analyzers
Two basic types of network analyzer include:
- Scalar Network Analyzer (SNA) which measures amplitude properties only
- Vector Network Analyzer (VNA) which measures both amplitude and phase properties.
What You Need To Know About Network Analyzer
- Network analyzer is used to measure reflection coefficients, transmission coefficients, insertion loss, return loss, S parameters and more. It takes care of measurement of components, devices and sub modules.
- Network analyzer provides high levels of accuracy in measurement due to vector error correction feature.
- Network analyzer consist of source and multiple receivers and measures broadband frequency signal using techniques such as power and frequency sweep.
- While doing measurement with network analyzer, it is hard to place a marker on the display, but interpretation of results is very easy.
- Network analyzer uses lower IF bandwidth filters.
- Network analyzer house both source and receiver and used for reflection and transmission coefficient measurement requiring both reference input, reflected and transmitted signals.
- Network analyzer can be used for amplitude and phase measurements.
- Network analyzer has an advanced error correction feature.
- 8757D is a scalar network analyzer and Model E5072A from Keysight Technologies is a vector network analyzer.
- It uses both frequency sweep and power sweep for measurement.
Difference Between Spectrum Analyzer And Network Analyzer In Tabular Form
| BASIS OF COMPARISON | SPECTRUM ANALYZER | NETWORK ANALYZER |
| Description | Spectrum analyzer is used to measure signal characteristics e.g carrier power level, harmonics, spurious, sidebands, phase nose etc on unknown signals. | Network analyzer is used to measure reflection coefficients, transmission coefficients, insertion loss, return loss, S parameters and more. It takes care of measurement of components, devices and sub modules. |
| Accuracy | It provides less accuracy in measurement. | It provides high levels of accuracy in measurement due to vector error correction feature. |
| Source Incorporation | It does not have source incorporated. It can demodulate and measure complex signals. | It consists of source and multiple receivers and measures broadband frequency signal using techniques such as power and frequency sweep. |
| Measurement | While doing measurements with spectrum analyzer, it is easy to place a marker on the display, but interpretation of results is difficult. | While doing measurement with network analyzer, it is hard to place a marker on the display, but interpretation of results is very easy. |
| Bandwidth | It uses higher IF bandwidth filters. | It uses lower IF bandwidth filters. |
| Components | It houses receivers only with single channel. | It houses both source and receiver and used for reflection and transmission coefficient measurement requiring both reference input, reflected and transmitted signals. |
| Use | It can be used for scalar component measurements only. They are not used for phase measurements. | It can be used for amplitude and phase measurements. |
| Advanced Error Feature | It does not have advanced error correction feature. | It has an advanced error correction feature. |
| Manufacture | The RSA3408A from Tektronix is real time spectrum analyzer. | 8757D is a scalar network analyzer and Model E5072A from Keysight Technologies is a vector network analyzer. |
| Frequency Sweep And Power Sweep | It uses only frequency sweep for measurement. | It uses both frequency sweep and power sweep for measurement. |