Method and apparatus for testing the output reflection coefficient of an automatic level controlled source

An apparatus for measuring the absolute value of the reflection coefficient between a transmission line of known characteristic impedance Z.sub.o and the output port of an automatic level controlled source, said apparatus comprising:

• a directional bridge having a transmission port to be coupled to the output port of the automatic level controlled source under test and having an input port and an output port;
• a signal generator coupled to the input port of the directional bridge to produce input test signals to perturb the output signal of the automatic level controlled source;
• and
• an amplitude modulation detector coupled to the output port of the directional bridge to detect the magnitude of the amplitude modulation component of the perturbed output signal of the automatic level controlled source.

A method of measuring the absolute value of the reflection coefficient between a transmission line of known characteristic impedance Z.sub.o and the output port of an automatic level controlled source, said method comprising the steps of:

• (a) activating the automatic level controlled source to produce an output signal of known amplitude V.sub.nom and frequency f.sub.s at the output port of the automatic level controlled source;
• (b) coupling the transmission line of characteristic impedance Z.sub.o to the output port of the automatic level controlled source;
• (c) applying a phase modulated test signal of known amplitude V.sub.t and carrier frequency f.sub.s through the transmission line to the output port of the automatic level controlled source to perturb the output signal of the automatic level controlled source;
• (d) detecting the peak to peak magnitude of the amplitude modulation component of the resulting perturbed output signal;
• and
• (e) determining the absolute value of the reflection coefficient from V.sub.t and the magnitude of the amplitude modulation component of the output signal.

A method of measuring the absolute value of the reflection coefficient between a transmission line of known characteristic impedance Z.sub.o and the output port of an automatic level controlled source, said method comprising the steps of:

• (a) activating the automatic level controlled source to produce an output signal of known amplitude V.sub.nom and frequency V.sub.s at the output port of the automatic level controlled source;
• (b) coupling the transmission line of characteristic impedance Z.sub.o to the output port of the automatic level controlled source;
• (c) applying a test signal of known amplitude V.sub.t and frequency f.sub.s through the transmission line to the output port of the automatic level controlled source to perturb the output signal of the automatic level controlled source;
• (d) repeatedly incrementing the phase of the test signal through a range of values which includes at least one maximum and one minimum of the amplitude of the output signal;
• (e) measuring the amplitude of the output signal at each value of the phase of the test signal;
• and
• (f) calculating the absolute value of the output reflection coefficient from V.sub.t and from the maximum and minimum values of the amplitude of the output signal.

An apparatus for measuring the absolute value of the reflection coefficient between a transmission line of known characteristic impedance Z.sub.o and the output port of an automatic level controlled source, said apparatus comprising:

• a directional bridge having a transmission port to be coupled to the output port of the automatic level controlled source under test and having an input port and an output port;
• a signal generator coupled to the input port of the directional bridge to produce input test signals to perturb the output signal of the automatic level controlled source;
• an amplitude detector coupled to the output port of the directional bridge to detect the amplitude of the perturbed output signal of the automatic level controlled source;
• and
• phase shifting means coupled to the signal generator for incrementing the phase of the test signal.

A method of measuring the absolute value of the reflection coefficient between a transmission line of known characteristic impedance Z.sub.o and the output port of an automatic level controlled source, said method comprising the steps of:

• (a) activating the automatic level controlled source to produce an output signal of known amplitude V.sub.nom and frequency f.sub.s at the output port of the automatic level controlled source;
• (b) coupling the transmission line of characteristic impedance Z.sub.o to the output port of the automatic level controlled source;
• (c) applying a test signal of known frequency distribution V(f.sub.t) through the transmission line to the output port of the automatic level controlled source to perturb the output signal of the automatic level controlled source;
• (d) detecting the magnitude of the amplitude modulation component of the resulting perturbed output signal;
• and
• (e) determining the absolute value of the reflection coefficient from V(f.sub.t) and the magnitude of the amplitude modulation component of the output signal.