K+K FXE is a multichannel high resolution phase and frequency counter, which measures the phase of up to 24 channels relative to a common reference signal (10 MHz), synchronous and without dead time. The resolution of a single shot measurement is 12.2 ps, the input frequency range is 4 kHz to 130 MHz, measurement rate is 1k sample/s
A K+K FXE system consists of up to 6 FXE measurement cards, which can be concatenated, each of them providing the phase of the respective input signals for 4 independent channels. Here, "phase" refers to the rapidly and continuously growing absolute value, rather than some phase offset relative to a reference signal.
From the measured phase values, the frequency of the inputs signals can be calculated. Also,
ratios between different channels may easily be determined, or some slowly varying phase drift
output signals of some device under test with respect to the input signal.
The precision of the measurement can be increased by long-term measuring and special mathematical functions, resulting for example in a frequency resolution of 4E-13 using a gate time of 1s.
Measurement results are available in real time and therefore can be used for controlling the phase of frequency generators. They are processed by the on-board microprocessor, which performs data reduction by e.g. averaging or computation of phase differences among different channels.
Additionally, a PC software for collection, presentation and archiving of measurement data is included. A Windows© Dynamic Link Library (DLL) provides for all the protocol handling and data recovery, delivering ASCII coded decimal floating point numbers to the application which are easily readable under all programming languages.
For highest precision applications, an optional reference phase scrambler K+K SCR may be mounted on the master board, which under control of the microprocessor varies the phase of the reference 10MHz synchronously with the phase averaging intervals, thereby allowing to average over the systematic error residuals of the electronics. With K+K SCR installed, the phase determination noise floor of the system is as low as 1ps for a 1s averaging interval.
The following FXE optional expansions are available: