Agilent Technologies S GSM, 8922M manual ⎛ RFin 20 ⎞

Using RF Rise Triggering

Effect of the RF Generator on RF Analyzer Measurements

Making Measurements

Advanced Features

•SMS Cell Broadcast - the SMS CB screen allows you to test whether the mobile phone is capable of correctly receiving and displaying a message sent from a base station using the Short Message Service (SMS) Cell Broadcast protocol. This screen can be accessed by highlighting the More field in any main screen and selecting SMS CB.

When using RF Rise triggering of measurements, the Trigger Delay should be adjusted so that the wanted data is captured during the sampling process. The actual measurement is made at the Trigger Delay time after the RF Rise. When changing from RF Rise triggering to another trigger mode, the Trigger Delay should be adjusted to the appropriate value as the default Trigger Delay is not automatically restored.

Example: In the Agilent 8922M/S, when using the RF Rise, a Trig- ger Delay of 0 is recommended. When changing from RF Rise to Ext Demod trigger mode, the default value of 473.4T should be re-entered for Trigger Delay.

The value 473.4T is derived from the 468.75 bits of delay between downlink and uplink plus the 4.7 bits of modula- tion delay inside the Agilent 8922M/S. All timing is refer- enced to the beginning of bit zero on the downlink TCH timeslot, (DCH or BCCH timeslot if TCH is not active.)

When the RF Generator is set to a high level relative to the analyzer RF input, some error may be introduced in the analyzer’s power detector. This is due to the isolation limits between generator and analyzer on the RF IN/OUT port. This only occurs when the RF Generator and RF Analyzer share the RF IN/OUT port. If the

RF Generator uses the AUX RF OUT port, no error occurs.

⎛	⎛ RFin –20⎞	⎛ RFgen + 14⎞			⎞
	⎝ -----------10--------------⎠	⎝	------------------------------	⎠
⎜			10		⎟
Error = 10 LOG⎜10	+ 10				⎟ –( RFin –20)dBm
⎜					⎟
⎝					⎠

RFin is the amplitude in dBm of the signal into the RF IN/OUT port. Normally the setting in dBm of the RF Analyzer Amplitude. RFgen is the setting in dBm of the RF Generator.

Because the two components are not always in phase, the actual error will often be slightly less.

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