Written by  May 26, 2011 - 194 Views

MMDVM board for Arduino Due Featured

To build a multimode digital repeater, G4KLX have developped a complete software called MMDVM (Multimode Digital Voice Modem). It is compatible of main digital modes (to date, C4FM, DSTAR and DMR).

MMDVM Board 3 1MMDVM F5UII Final 1This board interfac on one side transmitter and receiver and, on the second hand the Arduino Due. A computer (such as a Raspberry Pi for example) is connect via USB to the Arduino. This provide a complete controler for numerical repeater.

I design this PCB, like some other OM, with components in conventional sizes (DIL integrated circuit, resistors quarter-Watt, …). There is still a quite small component that is the TCXO . To eliminate an CMS component, I chose to install a HCMOS TCXO directly compatible of 3.3V expected voltage of the Arduino. The selected reference is the FOX924B-12 with an announced stability of +/- 2.5 ppm.

I replaced the bulky components (in TO220 housings) with equivalent components in TO92 case. The tests are to be carried out. However, even the largest components can be positioned, as I left the possibility of mounting one or the other versions. The board plugs directly on Arduino Due.

 

 

 

Schema MMDVM F5UII v1.1 1024x723

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