Design and Implementation of an Equalizer for Amplitude-Shift Keying (ASK) Modulation using LabVIEW and USRP-2900
ASK-based audio transmission system with equalization, ADC/DAC processing, and LabVIEW–USRP implementation
This project focuses on the design and implementation of an equalizer for Amplitude-Shift Keying (ASK) modulation using NI LabVIEW and USRP-2900 hardware.
The system is designed to transmit audio between a transmitter and receiver while using:
- ASK modulation and demodulation
- DSP-based equalization
- ADC and DAC conversion
- LabVIEW-based system design
- USRP-2900 RF communication hardware
The project demonstrates how digital communication, modulation theory, and practical DSP techniques can be combined into a complete transmission chain for audio signals.
The goal of the project is to transfer sound between transmitter and receiver using ASK modulation while improving signal quality through DSP and equalization techniques.
The system aims to:
- transmit audio through a communication channel
- represent the signal digitally via ADC
- modulate and demodulate the data using ASK
- suppress distortion and periodic noise
- recover the signal through DAC
- improve output quality using a multi-channel equalizer
ASK is one of the classical digital modulation methods, but real communication channels introduce:
- noise
- distortion
- fading-related degradation
- imperfect recovery conditions
This project addresses those issues through a practical LabVIEW implementation that combines:
- modulation
- demodulation
- equalization
- digital filtering
- signal recovery
It is a strong example of a hands-on communication systems project bridging theory and implementation.
.
├── EE_3001_Term_Project.pdf # Full project report
├── *.vi # LabVIEW transmitter, receiver, and DSP blocks
├── adc.m # MATLAB-based ADC processing script
├── dac.m # MATLAB-based DAC processing script
└── related project assets # Supporting files and LabVIEW resources
The report describes the full signal path as:
Song + periodic noise → ASK transmitter → channel → ASK receiver → equalizer → output sound
This architecture includes both communication and DSP enhancement stages.
- Input audio
- Noise addition
- ADC processing
- ASK modulation (TX)
- Transmission through channel
- ASK demodulation (RX)
- Equalization
- DAC processing
- Audio playback
- NI LabVIEW
- MATLAB for ADC and DAC helper processing
- NI USRP-2900
- RF coaxial cables with SMA connectors
- communication system test setup for TX/RX stages
The transmitter side converts the incoming signal into a digital representation and prepares it for ASK modulation.
The report explains that the TX side includes:
- message input
- added periodic noise
- ADC conversion
- symbol mapping
- pulse shaping
- upsampling
- carrier modulation
The ASK symbol mapping is described using two amplitude levels for binary 0 and 1, followed by pulse shaping and carrier multiplication.
The ADC stage is implemented using an external MATLAB script (adc.m) called from LabVIEW.
According to the report, this stage includes:
- combining the reference signal with a chosen noise signal
- quantization using 16 bits
- binary conversion
- reshaping the output into a bitstream
The report notes that 65536 quantization levels are created between -1 and 1, corresponding to 16-bit conversion.
A practical synchronization issue was observed between TX and RX.
The report explains that:
- data transfer initially had a large delay
- RX behaved like a buffer
- the NI-USRP configure section was adjusted
- delay was stabilized to 20 seconds
This is a valuable real-world engineering detail showing that the project tackled not only signal theory but also practical system timing.
The receiver estimates frame samples and performs:
- band-pass filtering
- demodulation
- pulse shaping filtering
- downsampling
- matched filtering
- decision making
The recovered signal is then passed to the equalizer and eventually to DAC and audio playback blocks.
The DAC stage converts digital information back into floating-point analog-like values.
The report states that the DAC side:
- reconstructs 16-bit values from binary groups
- maps them back into partition values
- restores the corrected signal into floating-point output form
This completes the end-to-end digital communication chain.
One of the strongest parts of the project is the 3-channel equalizer implemented in the receiver DSP section.
The equalizer is divided into:
-
Channel 1: 20 Hz – 2 kHz
Covers bass and midrange -
Channel 2: 2 kHz – 8 kHz
Covers upper-midrange and presence -
Channel 3: 8 kHz – 20 kHz
Covers brilliance / treble
The report states that each channel is implemented using Butterworth Sallen-Key low-pass and high-pass filters, allowing controlled enhancement or attenuation of different frequency bands.
A separate volume control is also included for overall output adjustment.
To listen to the reconstructed signal, a playback block is used in the receiver.
The report states that:
- playback sampling frequency was set to 8000 Hz
- bit depth was set to 16 bits/sample
This allowed the transmitted signal to be successfully played after modulation, demodulation, and reconstruction.
This project is valuable because it combines several major topics into one system:
- digital communication systems
- ASK modulation and demodulation
- LabVIEW-based SDR workflow
- ADC and DAC logic
- DSP equalization
- audio-focused channel improvement
It is not just a simulation or a block-level academic example; it is a practical communication chain built with real hardware and software tools.
- Select or load a song signal
- Add periodic noise
- Convert the analog-like signal into digital form using ADC logic
- Modulate the bitstream using ASK in LabVIEW
- Transmit through USRP-2900
- Receive and demodulate the signal
- Apply equalization across 3 frequency channels
- Convert digital signal back through DAC
- Play the resulting sound
This repository is useful for anyone interested in:
- communication systems
- digital modulation
- software-defined radio workflows
- LabVIEW project design
- DSP equalization
- ADC and DAC modeling
- practical ASK system implementation
It can serve as a reference for:
- undergraduate communications labs
- DSP projects
- SDR-based educational projects
- LabVIEW + RF system demonstrations
The repository is supported by the full project report:
EE_3001_Term_Project.pdf
The report includes:
- project objective
- ASK TX and RX design
- ADC and DAC details
- synchronization strategy
- equalizer design
- playing audio stage
- final conclusions
- Oğuzhan Alasulu
- Furkan Durmuş
GitHub repository owner: @alasulu
@misc{alasulu_labview_ask_equalizer,
author = {Oğuzhan Alasulu and Furkan Durmuş},
title = {LABVIEW Equalizer ASK Modulation Project},
year = {2026},
howpublished = {\url{https://github.com/alasulu/LABVIEW-Equalizer-ASK-Modulation-Project}}
}This project demonstrates how ASK modulation, DSP equalization, ADC/DAC conversion, and LabVIEW-based SDR design can be combined into a complete and practical audio communication system.
Please arrange the sample rate of filters to obtain the graph for seeing FFT Waveform alteration.