Frequently Asked Questions for our point2point modules

What type of fibre optic connectors can I use with PPM's systems

Optical Connectors are critical to the performance of a fibre optic link. All PPM's products use FC/APC connectors to minimse back reflection of light into the laser. PPM recommend the use of Huber & Suhner part number FCPC-Z/M-A601 which are FC/APC narrow key connectors offering >60dB return loss

I have connected the fibre but the receiver module still has a red LED on?

It is very easy for a fibre end to be contaminated with dirt. All PPM equipment is supplied with basic cleaning kits. It is always recommended that a fibre end is cleaned before inserting into the connector. Also, FC/APC connectors have a sinlge slot 'key' position that must be mated first before the thread is tightened

What is the level of Shielding Effectiveness

PPM cannot guarantee shielding effectiveness as the number of variables to take into account are countless. We have many satisfied customers in the automotive and military markets using modules in fields regularly exceeding 200V/m and even as high as 30kV/m. PPM would be happy to make demonstration equipment to prove performance in a particular application.

What is the maximum input level

For our point2point AC links the P1dB point is 0dBm. The maximum input level before damage occurs is +3dBm for a continuous signal and up to +15dBm for intermittant signals

For our point2point DC links the maximum input level is set at the factory. The table below shows the different inout options and the max input for each

What is the minimum detectable signal

For our point2point AC links the minimum detectable signal is limited by the output noise floor of the receive module. Noise figures for the links are specified on the datasheets. A table of typical performance is shown below:

The calculation used to obtain the figures above is:
Minimum Detectable Signal = -174 + Noise Figure (NF) + 10log10 (MBW)

Useful operating range - Useful operating voltage range over which operation is guaranteed

Extreme operating range - Range over which unit is expected to surive without EOS

For our point2point DC links they have a ADC/DAC conversion system built in. This gives 12 bit resolution. A +/-1V output receive module has a noise floor of around 5mV in 10MHz

What are the NiHM Battery charge and discharge times

The NiHM Battery charge time @ 2A for the 3.6Ah battery is -<2 hours and the 2Ah battery is -<1 hours

The NiMH Battery discharge time for the 3.6Ah is 8 hours for the DC modules and 15 hours for the AC modules

The NiMH Battery discharge time for the 2Ah is 4 hours for the DC modules and 8 hours for the AC modules