Agilent Technologies 8922 manual Pmfdata J11, MHz Ref B J233, Nsmifclk J21

Module I/O Specifications

A5 Premodulation Filter and NSM

From A34 GSM-RTI Assembly
		PMF_DATA J1(1)
	Level:	TTL
	Rate:	270.833 kbps
	Format:	Non-differential data encoded

The PMF_DATA signal is difficult to measure accurately without a high speed oscilloscope or logic analyzer. Using a Spectrum Analyzer, an increased noise floor can be seen when probed about the centre frequency of 270 kHz. Using an oscilloscope, the signal can be measured at 4.4 Vp-p. On a DVM, 2.25 Vdc.

From A15 Reference GSM-RTI Assembly

10 MHz Ref B J2(33)
Frequency:	10 MHz ± 500 Hz
Wave Shape:	Sine
Level:	>10 dBm
Harmonics:	< −25 dBc

	The 10 MHz Reference signal can be measured on an oscilloscope at 880 mVrms and
	2.6 Vp-p. On a Spectrum Analyzer, the marker will be approximately +10dBm.
NOTE:	The Premodulation Filter and NSM assembly are used to convert User Digital Data and
	clock signals into GMSK.

Outputs

To A27 DAC/Upconverter

	NSM_IF_CLK J2(1)
Frequency:		17.3333 MHz ± 250 Hz
Level:		TTL

The NSM_CLK signal can be sensed on the SERVICE Screen using the

’nsm_pmf_clk_pres_int_sense’ latch, a value of 1 for lock and ’0’ for OOL (Out Of Lock) state. An OOL condition can cause high phase and frequency error problems. See Figure 4-1 on page 12-12 for typical oscilloscope readings. On a Spectrum Analyzer, the peak marker should be >+6 dBm.

12-11