• AM-AM/AM-PM IN A C-BAND TELEMETRY TRANSMITTER USING 16-APSK

      Baxter, Jason; Perrins, Erik; DePardo, Dan; University of Kansas, Electrical Engineering & Computer Science Department (International Foundation for Telemetering, 2018-11)
      Due to the economic importance of spectrum allocation, modulation schemes traditionally used in telemetry are being replaced with more spectrally efficient schemes. Amplitude and Phase Shift Keying (APSK) is one modulation scheme being considered for implementation in aeronautical telemetry. However, an APSK modulated signal is vulnerable to nonlinearities of a transmitter’s RF power amplifier (PA). Driving a PA into saturation produces two undesired nonlinearities: amplitude-to-amplitude modulation (AM-AM) and amplitude-to-phase modulation (AMPM). This paper characterizes the PA in a C-Band transmitter using a 16-APSK test signal in terms of these nonlinearities.
    • INITIAL OBSERVATIONS OF 16-APSK USE IN C-BAND AERONAUTICAL TELEMETRY

      DePardo, Dan; University of Kansas, Information and Telecommunication Technology Center (International Foundation for Telemetering, 2018-11)
      The implementation of more advanced modulation formats such as Amplitude Phase Shift Keying (APSK), which can be spectrally more efficient and potentially less susceptible to adjacent channel interference than current aeronautical telemetry modulation schemes, could serve to mitigate telemetry frequency spectrum reductions and reallocations. This paper will detail initial laboratory transmitter measurements and observations of 16-APSK modulation performance in comparison to SOQPSK-TG.