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Hello Jerry,

1. There is a relationship between the CAN Bus transmission distance and data rates with faster data rates generally requiring shorter distances; however, the calculation of the maximum bus length at a specified date rate depends on more factors than just the data rate and cable length / propagation delay.  It includes the settings / performance of the CAN controller which determine when the bus is sampled.   Usually, this sample point is set as a quantized fraction of the bit time and may be adjusted as part of the system commissioning.  

CAN uses an arbitration scheme where two or more nodes determine who will control the bus by all writing data at the same time and confirming that the bus state is as they wrote.  When a node reads back something different, then it has lost the arbitration, disconnects and waits for the bus to become idle before trying again.  This is possible because the recessive state ("1") is high-impedance and the dominant state ("0") is driven and so a dominant bit will overwrite a recessive bit.  This means that the node needs to wait for a full round trip before sampling the bus.

The total round trip delay in the bus is twice the sum of the transceiver propagation delay, controller propagation delay and cable delay and this needs to be smaller than the time of the bit sample point which is some fraction of the total bit time which is equivalent to the data rate.

This is discussed in the technical article Optimizing CAN Node Bit Timing to Accommodate Digital Isolator Propagation Delays.

Note that depending on the network wiring quality, there may be some additional delays factored in to allow reflections and ringing to decay before the sampling point.

2. Generating an eye-diagram would be a common analysis method for analyzing the signal quality.  Searching on "CAN bus eye diagram" returns a good number of different sources and videos discussing this method. 

Eric