A typical phase noise performance for
156.25MHz reference clock input from the SMA100B is shown in Figure 5-1.
LMKDB1108EVM was configured in cascade mode to
get these measurements, which were obtained by following these steps:
- SMA100B → LMKDB1108EVM input.
Then, LMKDB1108EVM to secondary LMKDB1108 EVM. This was done to get a fast
slew rate at the input. Other methods like clipping a circuit can be used to
get a desired slew rate and square wave form as well outputted from the
SMA100B.
- Output phase noise is
measured through a Balun to the differential waveform from the LMKDB1108
into a single-ended waveform for the phase noise analyzer.