Tait TB8100 User Manual page 244

V
valid signal
VSWR
W
Watchdog
234 Glossary
A valid signal is a signal that the receiver responds to by opening
the receiver gate. A signal is valid for example when it is stronger
than a minimum level and when it has the specified subtone.
Voltage Standing Wave Ratio (VSWR) is the ratio of the
maximum peak voltage anywhere on the transmission line to the
minimum value anywhere on the transmission line. A perfectly
matched line has a VSWR of 1:1. A high ratio indicates that the
antenna subsystem is poorly matched.
A watchdog circuit checks that the system is still responding. If
the system does not respond (because the firmware has locked
up), the circuit resets the system.
© Tait Electronics Limited December 2007