Choosing Proper demux for Ultrasonic pulser


Hi everyone,
I do not have an electrical background and for my project, I need to design a multiplexer switch. I have an input signal and I want to be able to switch it between different transducers with some time lag. So I am using a demultiplexer for that reason but I am confused about what to pick.

My signal can be Analog or digital, I want low impedance (lower than my BNC cable which has 50ohm), the signals that I want to transfer are 50-400V and I want to use Arduino for the controlling part of it. I do not want to lose bandwidth (0.2 - 32 MHz analog bandwidth), and I want a very low Time_on/Time_off, basically lower than 100ns (I am not sure how important this limit is yet). I am using this for ultrasonic pulse transducers that is why I want low noises on it. Also on the pulser card, it is written 14 bit which I assume is the resolution for A/D.

I will be grateful if someone can help me.