Receiver capable of reliably detecting a failure

A receiver comprising:

• a receiver filter having a receiver frequency pass band and a receiver frequency attenuation band for filtering an input receiver signal into a filtered receiver signal;
• a pilot oscillator for generating a pilot oscillation signal having a pilot frequency in said receiver frequency attenuation band;
• a coupler connected to said receiver filter and to said pilot oscillator for coupling said pilot oscillation signal to said filtered receiver signal to form a coupled signal;
• a low noise amplifier connected to said coupler for amplifying said coupled signal into an amplified signal which comprises an amplified receiver signal component derived from said filtered receiver signal and an amplified pilot oscillation signal component derived from said pilot oscillation signal;
• a branching filter connected to said low noise amplifier for branching said amplified signal into said amplified receiver signal component and said amplified pilot oscillation signal component;
• a receiver terminal connected to an output of said branching filter for receiving said amplified receiver signal component from said branching filter;
• pilot signal detector means connected to said branching filter for detecting only said amplified pilot oscillation signal component to produce a direct pilot signal;
• and
• failure monitoring means connected to said pilot signal detector means for monitoring said direct pilot signal to produce a fault signal when said direct pilot signal is found faulty.