Microphonics

[MDOC]

I've seen microphonic-related problems on certain modems and LNBs (C-Band). Anyone here point me the way to solve this problem, or point to a reference that not only describes it, but also offers at least a theory of its cause? Thanks

 

[jcm]

Vibration (Oilcanning) of a cover over a microstrip can cause microphonics problems. Stiffen the cover or dampen the cover currents with absorber to see if it helps. Also keep the microstrip channel as narrow as practical.

 

[Iden]

The capacitance between leads and shield can induce microphonics. Try securely grounding the shield if there is one, or lifting the shield. If no shield exists and it is practical, use a shielded Ethernet cable. Without further details, it may be the connector, not the cable. Again, poor connection results in reflected power, induction, capacitance; all relating to the principles of the microphone.

Another solution may be a cap across the lines, but it is tricky with high speed Network. A cap across the leads has helped many times in other applications, such as Audio.
Merv

 

[nbucska]

Some ceramic CAPs may be microphonic, especially if they get polarized.( Hi V, hi temp.)

<nbucska@pcperipherals.com>