Abstract: A monitoring system which converts a desired radio frequency signal to an absolute value, detects the peak value of the signal, converts the peak value to a corresponding digital signal and processes the converted signal by a micro-computer to determine percent modulation of the signal and displays the result to the user. A plurality of signals may be monitored at the same time by multiplexing each signal onto a common signal line. The system my be remotely operated over an RS-232 line connected to a personal computer. The system also may be programmed with various alarm conditions such that when a monitored parameter falls outside of the desired range, the user is alerted to such condition.