BNC PB-5 - Manual (Page 4)

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FIGURE 1. Block Diagram of Model PB-5 Precision Pulse Generator
The Trigger Out Generator provides a pulse synchronized with the beginning of the rep-
rate generator or the External Pulse Input. This provides synchronization with the target
instrument.
The pulse Rep-Rate, Delay, and Width Generators are controlled by the Range Selector
and the associated 10-bit DAC voltage. The pulse rise and fall times are selected via the
µC selector bus, providing shape control to the output amplifiers.
Temperature Sensor information is sent to the µC which in turn operates the
Temperature Trim DAC. Very fine adjustments (error corrections) are made to the
amplitude every 5 minutes. When in the Ramp mode, corrections are made only
between ramp cycles.
The RS-232 port provides connection to a computer from a remote location. All the
functions can be remotely controlled by a PC running PB5 HOST program, a PC running
HyperTerminal program, or by a standard terminal.
The pulse amplitude is set by a 16-bit DAC referenced to an accurate voltage source. A
high-gain, low-drift amplifier buffers this voltage source. The output zero level is set by
a zero-trim DAC controlling the buffer amplifier. During factory calibration the
instrument is set so that the 0 to10 volt range can be adjusted within the precision
specified (150 µV). The output attenuator has ten selections that produce attenuation