3-11 FM and Phase Modulation Calibration
Calibration
3-30
PN: 10370-10386 Rev. B
MG362x1A MM
Ext FM ADC Offset
(Requires Freq Ref, Mod Processor) Connect equipment as shown in
1.
Disconnect any cable to the Ext FM input.
2.
Set PLLmod mode = 2 (LNFM), Mod source = 1 (External), FM_HPF = 0 (DC coupled)
3.
Set FM_POL = 1 (not inverted), FM_Mute = 0 (not muted)
4.
Set FM meter averaging time = 1 sec.
5.
Allow >1sec for transients to settle. Read meter average output to a resolution of 1LSB. (To see meter
output with 1LSB resolution, the meter output will have to be captured upstream of decimal conversion
and scaling that is for the front panel display). Average several readings, if necessary, to get an
indication that is stable to within 1LSB.
6.
Adjust “Ext FM ADC Offset” (Range is –2^11 to 2^11) to make meter average output = 0 LSB. (1 LSB of
Ext FM ADC Offset is equivalent to 1LSB of Meter output, so this should converge rapidly).
Ext FM ADC Offset
(Requires Freq Ref, Mod Processor) Connect equipment as shown in
1.
Disconnect any cable to the Ext FM input.
2.
Set PLLmod mode = 2 (LNFM), Mod source = 1 (External), FM_HPF = 0 (DC coupled)
3.
Set FM_POL = 1 (not inverted), FM_Mute = 0 (not muted)
4.
Set FM meter averaging time = 1 sec.
5.
Allow >1sec for transients to settle. Read meter average output to a resolution of 1LSB. (To see meter
output with 1LSB resolution, the meter output will have to be captured upstream of decimal conversion
and scaling that is for the front panel display). Average several readings, if necessary, to get an
indication that is stable to within 1LSB.
6.
Adjust “Ext FM ADC Offset” (Range is -2^11 to 2^11) to make meter average output = 0 LSB. (1LSB of
Ext FM ADC Offset is equivalent to 1LSB of Meter output, so this should converge rapidly).
7.
Save the “Ext FM ADC Offset” offset value to the FM cal table. This cal value will be re-applied to the Ext
FM ADC Offset register at MG362x1A boot-up and reset.
Note
Allow MG362x1A to operate at constant room temperature for 30 minutes before beginning
calibrations.
Summary of Contents for Rubidium MG362 1A Series
Page 12: ...Contents 10 PN 10370 10386 Rev B MG362x1A MM ...
Page 16: ...1 9 ESD Requirements General Information 1 4 PN 10370 10386 Rev B MG362x1A MM ...
Page 30: ...2 6 RF Deck Assemblies Functional Description 2 14 PN 10370 10386 Rev B MG362x1A MM ...
Page 66: ...3 11 FM and Phase Modulation Calibration Calibration 3 36 PN 10370 10386 Rev B MG362x1A MM ...
Page 292: ...B 5 Self Test Messages Instrument Messages B 8 PN 10370 10386 Rev B MG362x1A MM ...
Page 293: ......