Measurement of intermodulation and a discussion of dynamic range in a ruby traveling-wave maser

This paper reports measurements of intermodulation in a ruby traveling-wave maser. The power level at frequency 2f
2
-f
1
was measured when strong signals at frequencies f
1
and f
2
were applied to the maser. In agreement with theoretical predictions, the intermodulation level was found to be extremely weak. Results of the measurement can be expressed as P(2f
2
- f
1
) = 2P(f
2
) - P(f
1
) - 95 where f
1
=4110 Mc, f
2
=4140 Mc and the powers are measured in dbm. The pertinent characteristics of traveling-wave masers are summarized in a concluding Section.