How to use of the Spectrum analyzer

Because it had borrowed the Spectrum analyzer from Rade Schwarz Japan Ltd. to measure outputting waveform of AM wireless mike, was used after a long time.

What is the Spectrum analyzer ?

Spectrum analyzer (Spectrum analyzer)takes the frequency in a horizontal axis (X axis), and is a measuring instrument in the spindle (Y axis) like to the oscilloscope that displays decibel (dB) as for the voltage or the electric power waveform. It is called for short. There is no distinction between the voltage and the electric power because it is decibel (dB) display. (For instance, it is ten times in the voltage, and 100 times in the electric power in case of 20dB. )

It is a measuring instrument that can see the frequency element to be brief. It is called a spectrum analyzer.

Spectrum analyzer FSL18 of Rohde&Schwarz

Spectrum analyzer FSL18

This photograph is Spectrum analyzer FSL18 borrows from Rade Schwarz Japan Ltd. through the CQ publisher.

It is not like being able to buy it privately very much because it is the expensive one.

WidowsXP stands up when switching on, and this is a computer. It is not when trying though it is likely to be able to use with the mouse if the mouse is put up. It operated it with a right cursor.

The main specification of FSL18 of R&S

General usage of Spectrum analyzer

Outputting waveform of AM wireless mike measured with Spectrum analyzer

I want to do the design production AM and the one that the output of a wireless mike was measured with the Spectrum analyzer is this shape of waves.

It is the one that AM wireless mike was modulated by about 25% in the sine wave of 1.5kHz.

In this horizontal axis, a central frequency is 700kHz, the left end is 687.5kHz, and a right edge is 712.5kHz.

The level of the first upper and lower side-band wave of the plus or minus 700kHz1.5kHz is about -18 a dB compared with 700kHz signal carrier's level, and the theory street. It is for FM modulation element that in top and bottom of the next odd number side-band wave with level difference

The level of about the second side-band wave of the plus or minus 700kHz three kHz is about -40 a dB compared with the level of the first upper and lower side-band wave. I think this to be the one by the linearity of the modulation of the AM modulator and the one by residual FM the modulation element. However, there is no problem It is 1/100(Correspond to the distortion by 1%), and is an electric power, and because it is a voltage and 1/10,000 if it is -40 a dB. It is the very difficult generally one that makes to 1% or less at the distortion rate of the synthesis of the AM modulation.

Feature of Spectrum analyzer