Spectrum analyzer is an instrument to study the spectrum structure of electrical signals. It is used to measure signal parameters such as signal distortion, modulation, spectral purity, frequency stability and intermodulation distortion. It can be used to measure some parameters of circuit systems such as amplifiers and filters.
Spectrum analyzer is a multi-purpose electronic measuring instrument. The main function of the spectrum analysis system is to display the spectrum characteristics of the input signal in the frequency domain. Modern spectrum analyzer can display the analysis results in analog or digital way, and can analyze all radio frequency bands from VLF to sub-millimeter wave bands below 1 Hz. If the digital circuit and microprocessor are used in the instrument, it has the function of storage and operation, and the standard interface is configured, it is easy to form an automatic test system.
According to different signal processing methods there are two types of spectrum analyzer, including real-time spectrum analyzer and sweep-tuned spectrum analyzer.
Real-time Spectrum Analyzer
The function of real-time frequency analyzer is to display signal amplitude in frequency domain at the same instant, and its working principle is different. The corresponding filter and detector (Detector) transmit the signal to CRT or LCD display instrument through synchronous multiplex scanner. The advantage of real-time spectrum analyzer is that it can display the instantaneous response of periodic Random Waves. The disadvantage of real-time spectrum analyzer is that it is expensive and its performance is limited to the bandwidth range and the number of filters.
Sweep-tuned Spectrum Analyzer
Sweep-tuned spectrum analyzer is the most commonly used spectrum analyzer. Its basic structure is similar to the superheterodyne receiver. Its working principle is that the input signal is directly added to the mixer through the attenuator, and the tunable local oscillator is generated over time by the scanning generator synchronized with CRT. The frequency of oscillation varies linearly, and the IF signal is amplified after mixing the mixer with the input signal. The filter and detection are transmitted to the vertical direction plate of the CRT. Therefore, the corresponding relationship between the signal amplitude and frequency is displayed on the longitudinal axis of the CRT.
Spectrum analyzers tend to fall into four form factors: benchtop, portable, handheld and networked. Among them, bentop and handheld spectrum analyzers are common to use.
Benchtop
The bench top spectrum analyzer generally uses in a lab environment or production/manufacturing area. Bench top spectrum analyzer has historically offered better performance and specifications than the portable or handheld spectrum analyzer. Bench top spectrum analyzer can be plugged into AC power, and typically weigh more than 30 pound (14 kg).
Fig.1 Saluki S3532 Series Spectrum Analyzer
Saluki S3532 series spectrum analyzer is a benchtop spectrum analyzer. S3532 series spectrum analyzer reaches max. 7.5GHz with excellent performance. It has standard functions including pre-amplifier, AM/FM demodulation, interference analysis, limit line, OBW, ACPR etc. Meanwhile S3532 series spectrum analyzer is equiped with an optional tracking source and build-in CW source which can extend the ability of spectrum analyzer.
Portable
The portable spectrum analyzer is useful for any applications where the spectrum analyzer needs to be taken outside to make measurements or simply carried while in use. The portable spectrum analyzer has some attributes including: optional battery-powered operation to allow the user to move freely outside; clearly viewable display to allow the screen to be read in field conditions; light weight (usually less than 15 pounds (6.8 kg)).
Handheld
The handheld spectrum analyzer is useful for any application where the spectrum analyzer needs to be very light and small to carry in field conditions. The handheld spectrum analyzer has some attributes including: very low power consumption; battery-powered operation while in the field to allow the user to move freely outside; small size; light weight (usually less than 10 pounds (4.5 kg)).
Fig.2 Saluki S3332 Series Hnadheld Spectrum Analyzer
Saluki S3332 series spectrum analyzer is a handheld spectrum analyzer which is designed for field use. S3332 series spectrum analyzer has frequency range from 9kHz – 1.6GHz/3.2GHz. The high protection portable design, sturdy and durable can be used in laboratory, also more suitable for field mobile use. S3332 series spectrum analyzer also provides telecommunication ports such as USB and LAN for remote data collection and remote control. Optional tracking source is provide as an option for test need stimulus signal.
Networked
This form factor does not include a display and these devices are designed to enable a new class of geographically-distributed spectrum monitoring and analysis applications. The key attribute is the ability to connect the analyzer to a network and monitor such devices across a network. The networked spectrum analyzer has some attributes including: network-efficient data transfer; low power consumption, the ability to synchronize data captures across a network of analyzers; low cost to enable mass deployment.
