Calibration
3-11 FM and Phase Modulation Calibration
MG362x1A MM
PN: 10370-10386 Rev. B
3-33
LNFM Tune Gain for YIG High Band
This cal assumes “FM Tune Gain and FM Delay for YIG Low Band” has been completed. Connect equipment as
shown in
1.
Set Mod mode = 2 (Low Noise FM), Mod Source = 0 (Internal), FM Mod rate = 200 kHz, FM Polarity = 1
(Positive), FM HPF = 0 (DC coupled), GFM_1 = 1.00, DFM = 20. Set FM deviation = 20 kHz, FM_Mute =
0 (unmuted). Set carrier frequency = 5 GHz.
2.
Check FM PLL lock detector: Set SYN_SHIFT_REG_CR bits 14, 15, 16 (DOUTA, DOUTB, DOUTC) = 0,
1, 0 to connect FM lock detect to SYNTH_GP_MUX. Indication: 1 = Locked, 0 = Unlocked.
If the PLL is locked, then proceed. Otherwise, troubleshoot the lock error and go back to step 1.
3.
Set SYN_SHIFT_REG_CR bits 14, 15, 16 (DOUTA, DOUTB, DOUTC) = 0, 1, 1 to connect the Synth
module’s U93 ADC “YL_MON_OUT” to SYNTH_MISO. Set SYN_SHIFT_REG_CR bit 30
(PHASE_MON_EN) = 1) so U93 will monitor FM PLL PFD phase deviation. Use YLMON_CS and SCLK
to clock out the YLMON ADC data. The ADC is an LTC2365: After ~CS falling edge, the ADC puts out
16 serial bits comprised of 2 leading zeros, then 12 bits of data (MSB first) then two trailing zeros.
Observe the 12-bit ADC output to get an indication of phase error across the FM PLL PFD. Initial
YL_MON output for 200 kHz mod rate and 20 kHz deviation should be near 0.
4.
Mute FM. Set FM dev = 1.25 MHz. Unmute FM.
5.
Adjust FM Tune Gain DAC (within a range of 1310 to 2048) to minimize YL_MON ADC output.
6.
Calculate to 3 decimal places: GFM_1H = 1638/(Tune Gain DAC value)
7.
Save the calculated result for GFM_1H to GFM_0H, GFM_1H, GFM_2H, GFM_3H in the FM cal table.
(Cells EF13 to EF16 in MG362x1A Freq-FM-Spurs Calc 3P2-20.xlsx).
8.
Adjust FMdelay (within a range of 15 to 25) to minimize YL_MON ADC output. FMdelay is typically
19-21 at minimum YL_MON.
9.
Save FMdelay value “DFM_H” to the FM cal table (Cell EF19 in MG362x1A Freq-FM-Spurs
Calc 3P2 20.xlsx).
Содержание Rubidium MG362 1A Series
Страница 12: ...Contents 10 PN 10370 10386 Rev B MG362x1A MM ...
Страница 16: ...1 9 ESD Requirements General Information 1 4 PN 10370 10386 Rev B MG362x1A MM ...
Страница 30: ...2 6 RF Deck Assemblies Functional Description 2 14 PN 10370 10386 Rev B MG362x1A MM ...
Страница 66: ...3 11 FM and Phase Modulation Calibration Calibration 3 36 PN 10370 10386 Rev B MG362x1A MM ...
Страница 164: ...4 26 Pulse Modulation Tests with the 86100C Oscilloscope Performance Verification 4 98 PN 10370 10386 Rev B MG362x1A MM ...
Страница 292: ...B 5 Self Test Messages Instrument Messages B 8 PN 10370 10386 Rev B MG362x1A MM ...
Страница 293: ......