Connecting to TimeLab

As first measurement it is good to measure the noise floor of your new PFA. Follow these steps to connect the tinyPFA with TimeLab

  • Find a fairly stable clock source at 10 MHz and send this to both inputs (A and B) of the PFA and make sure the input levels are around -10dBm to 0dBm.
  • The input levels are measured by the PFA and show after Level: at the top of the display. The inputs can be up to +10dBm without damaging the PFA.
  • Select MEASURE/TAU and set to 0.1 s, set MEASURE/DECIMATION to 10
  • Select OUPUT/LOG/UNWRAPPED phase and activate OUTPUT/USB LOG.
  • Connect the PFA via its usb port to a computer running Timelab, After a couple of seconds the scrolling of the display will stop as TimeLab has not yet been started to accept data.
  • In Timelab activate "Acquire/Acquire from counter in talk only mode", select the USB serial port with the PFA and click on monitor and data from the PFA should scroll in the incoming data window (see below)
  • Enter all the data as shown below (your COM port may be different) for 10MHz input. You can select another trace duration. The "Sampling interval" in the acquisition dialog and the tau on the PFA must be the same (0.1 s)
  • Click on "Start Measure" and the noise floor measurement should start
  • During acquisition you can switch the measurement in TimeLab between ADEV, Phase and Frequency view without disturbing the measurement.
  • The ADEV should look like something below. You can abort the acquisition early by entering a SPACE character on the PC Keyboard