FM Sidetone phase comparison system

Abstract

Abstract A phase determining system particularly suitable for accurate phase determination in a multipath signal environment such as a city wherein gross frequency disturbances are present during deep multipath fades. In a first embodiment, a received signal containing phase ranging information is inputted both to a gross frequency disturbance detection circuit and to a delayed demodulator circuit such that gross frequency disturbances are predetected and removed from the phase determinations made over several cycles thereby improving the accuracy of the phase determination. In an alternative embodiment, an iterative type system determines the phase of an incoming FM ranging signal and inputs that determination to another phase determining circuit simultaneous with the delayed signal with its associated phase errors. The second phase determining circuit contains an error gate which will discard the determination when the signal error lies outside the error gate and will substitute an average signal in its place; however, if the delayed signal is within the error gate, the signal will be averaged along with the phase determined signal from the first phase meter. Additional stages of iteration may be provided for increased accuracy.

Inventors

• 👤 Manfred G Unkauf
• 👤 Derek V Harris
• 👤 Sven G Gustafsson

Bibliographic Details