Process for monitoring the output signals from a transmitting device

A process for monitoring a first signal and a second signal, each output from a transmitting device, said first and second signals being substantially sinusoidal and having a corresponding rotational frequency, offset-free, of the same amplitude, and ideally offset from each other by a 90.degree. phase difference comprising steps of:

• a) comparing each of said first and second signals with a reference voltage and producing a first binary auxiliary signal and a second auxiliary signal such that:
• said first binary auxiliary signal has a first binary state with each positive half-wave of the first signal and has a second binary state, said second binary state being the inverse of said first binary state, with each negative half-wave of the first signal;
• and
• said second binary auxiliary signal has said first binary state with each positive half-wave of the second signal and has said secondary binary state with each negative half-wave of the second signal;
• b) rectifying each of the first and second signals, thereby producing an absolute value of the first signal and an absolute value of the second signal;
• c) comparing said absolute value of the first signal and said absolute value of the second signal and producing a third binary auxiliary signal such that:
• said third binary auxiliary signal has said first binary state when said absolute value of the first signal is greater than said absolute value of the second signal;
• and
• said third binary auxiliary signal has said second binary state when said absolute value of the first signal is less than or equal to said absolute value of the second signal;
• d) X-OR gating said first and second auxiliary binary signals, thereby generating a fourth binary auxiliary signal;
• e) X-OR gating said fourth binary auxiliary signal and said third auxiliary binary signal thereby generating a first reference signal;
• f) monitoring said first reference signal's mark-to-space ratio for its adherence to a ratio of 1:1;
• g) generating a signal indicating a disturbance of the first and second signals when said mark-to-space ratio of said first reference signal deviates more than a specifiable threshold from the ratio of 1:1.