BNC 630 - Manual (Page 46)

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Data Modulation Mode Parameters
Figure 5.25-1: Data Modulation mode display
1. Baud Rate
In this field enter the frequency at which the data bits will modulate the output carrier. You may enter from 0 Hz to 130,000 Hz in
1 Hz steps.
The baud rate frequency is accurate to 1 Hz from 0 Hz to 3900 Hz. It is accurate to within 1% across its full range of 0 Hz to
130,000 Hz.
2. Mark Frequency
When the modulation data bit is a 1, the output is set to the Mark frequency. You may enter a frequency from 0 Hz (DC) to
21.5000000 MHz in .01 Hz steps.
3. Space Frequency
When the modulation data bit is a 0, the output is set to the Space frequency. You may enter a frequency from 0 Hz (DC) to
21.5000000 MHz in .01 Hz steps.
4. Data
This word appears when a valid modulation data message has been downloaded to the 630. Without a valid data message, the word
“Data” does not appear and the 630 operates in regular Internal FSK mode.
5. Level
In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1 dBm steps.
NOTE: For wideband FSK (where the difference between Mark and Space frequencies is > 1.0 MHz), the output level may shift
slightly between the mark and space frequencies. The 630 has internal leveling circuitry which is disabled in this mode, in order to
offer higher FSK modulation rates.
NOTE: The level specified is a 50 ohm LOADED level. This is the level of the signal which will appear across a 50 ohm load
connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.
Offset
You can enter an offset voltage for the output waveform. For more information on output offsets refer to section 4.4.
Ext Trigger Input
(rear panel connector)
In Data Modulation mode this input functions as an external trigger input. A logic low-to-high transition on this input will trigger
the transmission. This input has an internal pulldown resistor so that the input is held at a logic low when this input is left
unconnected. See section 2.0 for more information on the External Trigger Input.
Int FSK: 1,000 Hz Mark: 1,000,000.00 Hz
Space: 2,000,000.00 Hz Data -10.0 dBm
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