Search Length (Custom OFDM)
specifies the amount or length of Search Time input data that is included in the measurement pulse search. The VSA pulse search algorithm searches within the entire search length to find the first complete OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. burst that can be demodulated and analyzed. The burst can occur anywhere within the Search Length.
The Meas Setup " Time parameter is not available (disabled) when the VSA is in modulation analysis mode.
The VSA searches within the specified and demodulates the first complete pulse (or burst) found. The pulse can occur anywhere within the . Pulses beyond the first complete pulse are disregarded and are not demodulated. In order for the pulse search algorithm to detect a pulse edge, the pulse must be at least 15 dB above the noise floor. The resultant pulse is then demodulated. However, you can use the Pulse Search Threshold properties to customize the pulse search criteria to capture a particular type of burst for the measurement.
Longer pulse lengths increase the measurement time but make it more likely that a pulse will be found. If a pulse is not found a PULSE NOT FOUND status message is displayed.
See Also
