So, CRO displays the frequency spectrum of RF signal on its CRT screen. The output of detector is given to vertical deflection plate of CRO. The amplified IF signal is applied to detector. IF amplifier amplifies the Intermediate Frequency (IF) signal, i.e. It produces an output, which is the difference of frequencies of the two signals that are applied to it. Mixer gets the inputs from Low pass filter and voltage tuned oscillator. Low Pass Filter (LPF) allows only the frequency components that are less than the cut-off frequency. If the signal amplitude is too large, then it can be attenuated by an input attenuator. The RF signal, which is to be analyzed is applied to input attenuator. The working of superheterodyne spectrum analyzer is mentioned below. Its block diagram is shown in below figure.

The spectrum analyzer, used for analyzing the signals are of RF range is called superheterodyne spectrum analyzer. So, CRO displays the frequency spectrum of AF signal on its CRT screen. This switch allows the detector outputs sequentially to the vertical deflection plate of CRO. The output of each band pass filter is given to a corresponding detector.Īll the detector outputs are connected to Electronic switch. It has a set of band pass filters and each one is designed for allowing a specific band of frequencies. The working of filter bank spectrum analyzer is mentioned below. The following figure shows the block diagram of filter bank spectrum analyzer. The spectrum analyzer, used for analyzing the signals are of AF range is called filter bank spectrum analyzer, or real time spectrum analyzer because it shows (displays) any variations in all input frequencies. Now, let us discuss about these two spectrum analyzers one by one.

We can classify the spectrum analyzers into the following two types. Here, x-axis represents frequency and y-axis represents the amplitude. Basically, it displays the energy distribution of a signal on its CRT screen. The electronic instrument, used for analyzing waves in frequency domain is called spectrum analyzer.

Spectrum network analyzer