8
driven to VL. When the EOD interval expires the P400 is ready to accept new trigger
pulses.
If the last programmed edge is programmed to be k ns after T0, the P400 will accept
triggers separated by (k + 60) ns up to the specified 10 MHz max. For very short
programmed delays, the P400 will typically externally trigger above 13 MHz. .
3.2
Block Diagram and Basic Functions
Figure 2. Block Diagram
The P400 contains the following logic blocks and functions:
TRIGGER MULTIPLEXER
. This circuit selects one of four possible trigger sources:
internal, external input, AC line input, or manual single-shot.
The internal trigger source is derived from the programmable DDS frequency
synthesizer. The DDS synthesizer can be programmed from 0.01 Hz to 10 MHz in
0.01 Hz steps.