BNC 630 - Manual (Page 41)

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5.22 Internal BPSK Mode
Introduction
The Internal BPSK mode generates a phase shift keyed signal of fixed amplitude. An internal timer is used as a modulating signal
to switch the output phase between 0 and 180 degrees at a specified rate. The modulation is suppressed carrier; i.e. no carrier energy
is present in the output waveform.
This mode is available under the “other” modes menu. To enter the Internal BPSK mode, press Mode, Clear, 1, 1
Internal BPSK Mode Parameters
The Internal BPSK mode has the following front panel display:
Figure 5.22-1: Internal BPSK mode display
1. Modulating Frequency
In this field enter the carrier phase switching frequency. You may enter from 0 Hz to 130,000 Hz in 1 Hz steps.
The internal modulating 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. Carrier Frequency
In this field enter the frequency of the carrier. You may enter from 0 Hz (DC) to 21.5000000 MHz in .01 Hz steps.
3. 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: 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
By pressing this key, you can enter an offset voltage for the output waveform. For more information on output offsets refer to
section 4.4.
Ext Gating Input
(rear panel connector)
This TTL compatible input can be used to turn the output signal on or off. A logic high voltage on this jack (+3V to +10V) will
turn off the output signal. A logic low voltage on this jack (0V to -10V) will leave the output signal on.
For further information on the Ext Gating Input, refer to section 2.0.
Int BPSK: 1,000 Hz
20,000,000.00 Hz -10.0 dBm
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