Clock Adjust (RFID)

Default: 0 Symbols (See RFID Standard Setups/Presets Table)

Range: -0.5 symbols to +0.5 symbols

Clock Adjust determines where the demodulator samples the symbol points.

The digital demodulator does not require symbol-clock timing signals to determine the location of symbols (detection decision points). Instead, the digital demodulator uses an algorithm to determine symbol locations.

Some digital communications systems contain non-linearities that can bias the digital demodulator's estimation of the symbol clock position. Use clock adjust to compensate for this "offset" and obtain a lower ASK Error or FSK Error.

The effects of changing clock adjust can be seen by displaying a constellation diagram or eye diagram. Increasing (or decreasing) clock adjust:

Shifts the detection-decision points in the constellation diagram.
Slides the eye diagram right or left (remember that in the eye diagram, the symbol locations remain in a fixed location on the display; therefore, changing the location of symbols has the effect of horizontally shifting the eye diagram).

Additional Tips

Here are some additional tips:

Specifying a clock adjust only affects the I/Q measured trace. It does not affect the I/Q reference trace.
Use the eye diagram with an eye length of one (1) to observe the accuracy of the symbol clock timing. May also want to monitor the ASK Error or the FSK Error in the Demod Summary Table trace while adjusting Clock Adjust to obtain the optimum symbol timing.
Clock Adjust is reset to 0.0 on power-up or when you click Preset to Standard...