mfkiwl / cuda-filterbank

Using CUDA and a Filterbank method to filter all 100 FM stations simultaneously

Overview

These programs implement a software defined reciever that channelzes all 100 FM stations using a uniform DFT filter bank. There are three programs.

1. The first program uses the UHD to control the USRP hardware and writes to shared memory.
2. The second program reads from shared memory, process the signal on the GPU using the C-API for CUDA, and writes the output to standard out.
3. The third program (SoX) receives the signal through a pipe and reads from standard input. SoX writes the audio to the sound card.

Computer hardware information

We are using Ubuntu 16.04 LTS and a Nvidia GeForce GTX 1080 Ti GPU.

Radio hardware information

We are using a generic scanner antenna (25-1300 MHz) connected to a custom bandpass filter (KR Electronics) passing the 20 MHz wide FM band (88-108 MHz). The BPF output is connected to a USRP B205mini-i, which is connected to the PC via USB3.0. The programs below shift the center of the FM band to zero frequency (zero-IF receiver) and the stations are separated using a filterbank implemented on the GPU. An FM station is demodulated and sample rate converted to 40 kSamples/second. The audio signal is piped to Sox for listening.

Software, drivers, libraries

These programs require the following software:

• USRP Hardware Driver (UHD)
• Boost C++ library (should be pre-installed)
• CUDA (we use CUDA 8.0)
• SoX - Sound eXchange

USRP stream program:

Compile Instructions:

usrp_stream4.cpp -o usrp_stream4 -luhd -lboost_system -lboost_thread -lboost_program_options

Execute Instructions: (NOTE: Launch this program after the filterbank3.)

./usrp_stream4.cpp --rate 20000000 --freq 98100000 --spb 16384 --type float

Filterbank program:

Compile Instructions:

nvcc filtbank3.cu -o filtbank3 -lcufft

Execute Instructions: (NOTE: Launch this program before usrp_stream4. The output of this program is piped to SoX for audio.)

./filtbank3 <radio station (i.e. 92.9)> | play --rate 40k -b 32 -c 1 -e float -t raw -