Highland T560, Technical Manual

Page: 14 / 49

14 T560MANK5.DOCX
3.6. Pulse Outputs
Four pulse outputs are provided, called channels A, B, C, and D. Outputs are +5 volt
CMOS levels with a 50-ohm source impedance. They can drive 5 volts into a non-
terminating load, or 2.5 volts into a 50-ohm load. Because they are source terminated, they
may drive a 50-ohm coaxial cable any distance into any termination impedance without
significant reflection problems. For example, a 100 ohm termination will provide a clean 0 to
+3.3 volt logic swing. External passive components can be used to convert to ECL or PECL
levels.
Each output is programmable for pulse delay and width relative to the trigger. If an output is
programmed for delay D, the actual output pulse will occur at D + 20 ns after the external
trigger, where 20 ns is the basic insertion delay of the T560. Pulse outputs are normally
active-high, but may be programmed to operate active-low.
Figure 3-3 Typical T560 channel outputs into 50 ohms. Risetime is 640 ps.