If a given relay has rise time of 50 picoseconds, a given digital pulse passing through it will have its rise time increased by 50 picoseconds. Now, if they have to travel through a matrix of five relays, its rise time will increase by 250 picoseconds. Now the frequency response after one relay is 20 GHz but after the fifth relay it is down to 4 GHz. So it’s important for the system designer to know how many relays or components its signals will pass through to determine if the components will work in his circuit.
