There are a number of factors that affect the how many IEDs can be supported.
- The impedance of the output
- The peak to peak voltage of the output
- The input impedance of the IEDs
- The minimum input voltage of the IEDs
Tekron clocks have an impedance of 120 Ω and an output voltage of 9 (Vp-p)
The equation for calculating the maximum IEDs is as follows
R is the input impedance of the AM IRIG-B input of the IEDs, in ohms.
V is the minimum input voltage of the AM IRIG-B input of the IEDs, in volts (peak to peak).
N is the maximum number of IEDs.
As a note this equation does not take into account the cable resistance and assumes that all IEDs are the same.
If a 120 Ω terminating resistor is added at the end the equation changes slightly as it reduces the maximum number of IEDs
The new equation is:
