When executing a trace data transfer from the 2650 or 2658 to a PC, the spectrum analyzer will return the trace data in hexadecimal format. In order to read the data values, these data points will need to be converted using the following equation.
'Ref level' - [(200 - 'HEX data converted to decimal') x 'resolution'] = 'data value'
Resolution value is derived from the scale setting:
10 dB/div: 0.4 dB
5 dB/div: 0.2 dB
2 dB/div: 0.08 dB
Returned HEX data point = 2A
Reference level of trace is set to 110 dBuV
Scale setting of trace = 10 dB/div
HEX data converted to decimal, 0x2A = 42 (dec)
Scale setting = 10 dB/div, so resolution is 0.4.
Enter values into equation:
110 - [(200 - 42) x 0.4] = 46.8
So for a HEX return data of 2A, the data point value is 46.8 dBuV.
To calculate associated frequency values for return trace data, divide span by number of points.