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Calibrating Analog FM Signals

The following procedure shows how to make an analog FM Calibration.

1. Set up the equipment as shown below.

   

   For signal generator, only ESG can be used in FM Deviation Calibration. 

2. Click on Waveform Setup in the tree view, and configure Carrier attributes in parameter view. 

   

   1. FM Scheme: select Analog in the drop-down menu.

   2. In the Carrier node, click on the on the right side of FM Deviation, and a FM Deviation Calibration Wizard will pop up.

3. Make sure the instruments connection is ready.

   

   1. Connect ESG RF OUTPUT to the RF INPUT of Spectrum Analyzer.

   2. Connect EXT 1 INPUT at the front of ESG to the I-OUT at the back of ESG

   3. Connect the ESG 10MHz OUT to the EXT REF IN of Spectrum Analyzer.

4. Measure the Frequency Offset according to the following procedures.

   

   1. Click the "Calibrate" button, so that a test waveform will be downloaded into the ESG ARB memory.

   2. Measure the frequency offset from the front panel of Spectrum Analyzer, according to the screen capture illustrated above.

      1. Press "Mode" on the front panel of Spectrum Analyzer, and select "Spectrum Analyzer".

      2. Press ”Freq Channel”, select ”Center Frequency”, and enter the value specified, which could be looked up on ESG.

      3. Press ”SPAN X Scale”, and then enter 200 KHz.

      4. Press ”Peak Search”, and record the marker value displayed on the upper right ”Mkr1 ___MHZ”.

      5. Calculate the Frequency Offset Value and enter it into Frequency Offset blank.

         (Frequency Offset = Marker Value - Center Freq. Value)

      6. Make sure desired FM Deviation (kHz) is the same as in the Carrier setup GUI, and then click on next.

5. Adjust the FM deviation

   

   1. Click "Apply" to apply the FM deviation to ESG now.

   2. Click "Finish" to let the settings take effect after waveform download.