AM Crosstalk in Unified Carrier Telemetry Systems.
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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Under the unified carrier concept several angle-modulated subcarriers are combined and phase modulated on an RF carrier. As a practical matter in a hardware system the angle-modulated subcarriers will contain a certain amount of amplitude ripple. Conceptually, a subcarrier with AM ripple can be viewed as a constant envelope subcarrier with a continuously varying modulation index. It follows that a continuous transfer of AM between the components in the unified carrier spectrum will occur due to the varying envelope modulation index of any data subcarrier. The report discusses in some detail the problem of crosstalk transferred to the PM carrier from a single subcarrier which is biphase modulated with PCM data. The implications to carrier false lock and tracking are studied. Analytic and experimental results are presented. Author