Downloading and Using Files
Downloads Directly into Pattern RAM (PRAM)
Chapter 4188
Modulating and Activating the Carrier
The following section explains how to modulate the carrier with the data downloaded to
PRAM, first from the front panel interface, and then via remote SCPI commands.
Via the Front Panel
1. Set the carrier frequency to 2.5 Ghz (
Frequency > 2.5 > GHz).
2. Set the carrier amplitude –10.0 dBm (
Amplitude > –10 > dBm).
3. Turn modulation on (press
Mod On/Off until the display annunciator reads MOD ON).
4. Activate the RF output (press
RF On/Off until the display annunciator reads RF ON).
Via the Remote Interface
Send the following SCPI commands to modulate and activate the carrier.
1. Set the carrier frequency to 2.5 Ghz:
[:SOURce]:FREQuency:FIXed 2.5GHZ
2. Set the carrier power to –10.0 dBm:
[:SOURce]:POWer[:LEVel][:IMMediate][:AMPLitude] -10.0DBM
3. Activate the modulation:
:OUTPut:MODulation[:STATe] ON
4. Activate the RF output:
:OUTPut[:STATe] ON
Viewing the PRAM Waveform
After the waveform data is written to PRAM, the data pattern can be viewed using an
oscilloscope. There is approximately a 12-symbol delay between a state change in the burst bit
and the corresponding effect at the RF out. This delay varies with symbol rate and filter
settings and requires compensation to advance the burst bit in the downloaded PRAM file.
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