DL9SEC DDS-VFO (small)
DL9SEC DDS-VFO
with DRM receiver frontend
 

 

Introduction


This project started in the middle of 2003, when i read some articles aboutExternal linkDRM (Digital radio mondiale) and found the website ofExternal linkChristoph Petermann (DF9CY), where he published some schematics for aExternal linkDRM demonstration receiver.

Because of my interests as radio amateur and engineer, i decided to build my own microcontrolled direct conversion receiver with a DDS-VFO. The first version of this receiver (downmixing the RF to a 12kHz IF) includes the microcontroler (with LCD, rotary encoder and keypad), the DDS-unit, the mixer stage and the 12kHz-amplifier. The software for the MCU was very simple with a fix table of DRM station frequencies. It works fine for a first attempt, but there was a lot room for improvements...

DL9SEC DDS-VFO (large)

Fig. 1: View of the DDS-VFO

In autum 2003 i came in contact withExternal linkBurkhard Kainka (DK7JD), who did a lot of cuircuits for DRM reception, and we had alive exchange of ideas (many thanks to him for his support, he is a really great author and engineer).

Some months and discarded concepts later, i decided to separate the DDS-VFO and the DRM receiver, on the one hand to have a new nice and useful gadget in my ham shack (the VFO) and on the other hand to be more flexible with the DRM receiver. In this configuration i can test some further receiver concepts without roasting around the DDS, just plugging a new frontend. The result is shown in fig.1. Also the µC-firmware grew up and i added a lot of features described inExternal linkOperation.

The DDS-VFO/DRM-RX are not comercial products, but an amateur project and therefore provided "as is". This website is intended to be a proposal for hams and other amateurs. So all the schematics, layouts and the firmware sourcode can be downloaded and applied for free, as long as it´s for a non-comercial project. If there are questions, don´t be afraid to ask...

(Some of the pages aren´t ready for upload yet. They will be added as soon as possible...)

vy 73, Thorsten DL9SEC (External linkwww.dl9sec.de)

Introduction

Overview

DDS-VFO

DRM-RX

Operation

Conclusion

Downloads

 

Disclaimer

 

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Last update at 23.03.2005 by Thorsten Godau DL9SEC