Is it possible to measure the EVM of a Shaped-OQPSK signal using the VSA software, 89601A? Specifically, I am interested in measuring the EVM of a MIL-STD Shaped-OQPSK signal and an IRIG Shaped-OQPSK-TG signal.
It appears that I can measure the EVM of a standard OQPSK signal, but I do not know if this can be extended to a Shaped-OQPSK signal. Generation of a Shaped-OQPSK signal requires implementation of a frequency pulse shaping filter, but the User Defined Filter in the VSA software does not appear to be a frequency-pulse shaping filter. Rather, the User Defined Filter appears to filter streams of separate I and Q impulse trains. I have not been able to figure out how to translate a frequency-pulse shaping filter to an I/Q impulse filter and am wondering if such a translation is even possible.
It appears that I can measure the EVM of a standard OQPSK signal, but I do not know if this can be extended to a Shaped-OQPSK signal. Generation of a Shaped-OQPSK signal requires implementation of a frequency pulse shaping filter, but the User Defined Filter in the VSA software does not appear to be a frequency-pulse shaping filter. Rather, the User Defined Filter appears to filter streams of separate I and Q impulse trains. I have not been able to figure out how to translate a frequency-pulse shaping filter to an I/Q impulse filter and am wondering if such a translation is even possible.
Support for SOQPSK-TG (IRIG 106) was added in 89601B version 15.0.
This capability is not available in 89601A.
Regards -