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In my current project, I need to transmit 4 analog signals (A1, A2, A3 and A4) on a cable from one PCB to another. I am working at 3 VDC and the distance between them is relatively short (< 30 cm).

I am not comfortable with this situation since I have always worked within my PCB. I have read that the transmission needs to be differential, so I will transmit 9 wires : A1-, A1+, A2-, A2+, A3-, A3+, A4-, A4+ and GROUND.

What should be my configuration to make it work ? Or more precisely : what type of component should I use to transmit and receive the data on both ends ? Are there standard references ? Will the differential signals be digital or analog during the transmission ?

I may ask basic questions but I am a beginner at this, sorry...

Any help/advice will be greatly appreciated. :)

EDIT :

  • My PCB will need to pass the EMC certification, which is why I need to be careful with signals I am transmitting.
  • The analog signals are related to this ECG sensor : https://datasheets.maximintegrated.com/en/ds/MAX30001.pdf . It needs to inject and receive current on two pins and measure the voltage on two other pins.
  • The frequency of the current injected can reach 131 kHz based on the datasheet
  • I need to be as accurate as possible, which is why I need to transmit the analog signal as differentials
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  • \$\begingroup\$ Depending on your setup, you might not need anything special but, it all depends on the isolation requirements and the EM environment the two boards are in plus, what your signal quality expectations are.. \$\endgroup\$ – Andy aka Oct 8 '19 at 14:52
  • \$\begingroup\$ What sort of frequencies are you sending? (Please edit the info' into your question rather than as comments.) \$\endgroup\$ – TonyM Oct 8 '19 at 15:00
  • \$\begingroup\$ what accuracy must you maintain on the analog signals? 1 microvolt in 10MegaHertz bandwidth? or 0.1 volt in 10Hertz bandwidth? \$\endgroup\$ – analogsystemsrf Oct 8 '19 at 15:39
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    \$\begingroup\$ "10 kbit/s" sounds suspiciously digital to me. Without any further specifications, the answer could be 4 pieces of screened audio cable, and no components at all. \$\endgroup\$ – Simon B Oct 8 '19 at 16:06
  • \$\begingroup\$ @JackOfHearts What noise floor do you need on the analog cables? Are you feeding these into an ADC? What is the analog signals coming from? a sensor? \$\endgroup\$ – Voltage Spike Oct 8 '19 at 16:42
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Unless your requirements for bandwidth or noise immunity are extreme, ordinary ribbon cable and IDC connectors will be fine for this. I would recommend arranging the connections so that each pair of signals has a ground wire between them, to minimize crosstalk.

Here's an example.

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    \$\begingroup\$ And in many applications single ended analog transmission over ribbon cable should work just fine without having to resort to differential analog. \$\endgroup\$ – Michael Karas Oct 8 '19 at 15:13

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