Week 15 – The End

Work of this week This was the last whole week of GSoC 2017 and I mainly did bug fixes and code wrap up. Finally I created an executable app that is installed along with the gr-dab module so that users don't have to run the python script but can simply type the command "DABstep" to …

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Week 14 – Developer Mode

The GUI was extended about the developer mode this week and I put some finishing touches on the GUI. But first of all the most important news: The "DAB/DAB+ transceiver app" is now called "DABstep" and finally has a logo! Developer Mode The developer mode extends the regular user front end about the following widgets: …

Week 13 – Finishing the user frontend

I finished the user mode of my transceiver app! Receiver I did some minor improvements on the receiver, affecting visual things but also some system bug fixes. The following things were done in the last week: Add lookup tables for country and language Measure and display the SNR: this was achieved by adding the GNU …

Week 12 – A basic transceiver app

This week I continued my work on the GUI. I did some minor improvements for the receiver and implemented the basic functionality for the transmitter. Receiver improvements: Add file source as a second source option of receiving IQ samples (next to USRP) Add a record feature: writes the received and selected subchannel audio (in addition …

Week 11 – Graphical User Interface

This week I started creating the GUI for my DAB/DAB+ transceiver app. I divided the task into the following sub tasks: Create a principle design for the user interface Achieve basic functionality for reception Achieve basic functionality for transmission Add nice features and improve usability/design Add developer mode Create a principle design for the user …

Week 10 – Audio encoding

This week I finished the MPEG Audio Layer II encoder for DAB transmission and the MPEG 4 HE-AAC encoder for DAB+ transmission. Encoding the MPEG Audio Layer II for DAB As described in a former blog post, the DAB audio frame structure only slightly differs from the MPEG Audio Layer II structure. The major differences …

Week 09 – There is music in the air!

I solved the Reed Solomon issue! After implementing another Reed Solomon decoder (parts of libfec by KA9Q), both decoders would still not be able to correct any errors. Because I eliminated all possible prior issues and I excepted the possibility that both RS decoders were not properly implemented, the only remaining error source could be …

Week 08 – Reed Solomon

The Reed Solomon Issue The implementation of the DAB+ audio decoder (MPEG 4, AAC v2) stuck last week because the Reed Solomon (RS) decoder claimed to get solely frames with more than  5 errors which obviously cannot be corrected (It is a RS(120, 110, t=5) according to ETSI TS 102 563 clause 6.0 and 6.1). …

Week 07 – Audio decoding

Audio decoding The implementation of the audio decoding splits into two tasks: MPEG 1/2 Audio Layer II decoding for DAB audio frames MPEG 4 HE-AAC v2 decoding (with additional firecode check and Reed Solomon error repair with included interleaving) for DAB+ audio frames MPEG 1/2 Audio Layer II The MPEG 1/2 coding standard is a …

Week 06 – Debugging

I finally solved  the last issues in the encoding chain of the DAB transmitter! The problem: When I finished the transmission chain two weeks ago, I created a loop-back test for the FIC encoder which failed (see former post as well). The loopback test starts at the FIB source and goes through the whole encoding …