This frequency domain data is transmitted to the Video MCU, which processes the data into a histogram visualization in real-time. This microcontroller will sample the audio signal at a constant rate and perform a Fast Fourier Transform (FFT) to convert the signal into frequency domain. The signal is amplified and filtered and sent to the FFT MCU. First, the audio signal is inputted into the system through the audio jack. The data flow of our project runs rather linearly. For example, one can see not only the main pitch of a note from an instrument such as a saxophone but also the various harmonics that determine the timbre of the instrument. Being able to view a visualization of the frequency spectrum of audio is both interesting as a visual entertainment source to pair with music as well as a way to view the different frequency components assoicated with certain sounds or instruments.
We originally wanted to take audio input with a microphone but realized that input directly from another device offers clearer signals. We wanted to create a similar hardware based equalizer that could be built cheaply and interface with standard audio inputs and video outputs.
#SPECTRUM FLICKERY CHACNNELS SOFTWARE#
Our project idea was inspired by popular toys such as the T-Qualizer, and built in music visualizers in many software audio players such as Windows Media Player. High Level Design top Rationale & Inspiration Our device is able to display frequencies in audio of up to 4 kHz, which covers the majority of the frequency range of typical music which is the intended input of our project, as shown in this diagram. Using a male-to-male RCA video cable, the user can connect any standard NTSC television supporting resolutions of at least 160x200 to the device’s RCA video jack and display the visualization on the TV. Using a male-to-male 3.5mm audio cable, the user can connect any audio producing device such as a computer or MP3 player to the device’s 3.5mm audio jack and input an audio signal. Users are able to select various display options using a set of push buttons including the overall frequency range displayed and the amplitude scale, among others. The two microcontrollers handled separate tasks, with one performing the audio data acquisition and processing (hereafter referred to as the FFT MCU) and the other performing the visualization processing and video data transfer (hereafter referred to as the Video MCU). We were able to successfully display the frequency spectrum content of an audio signal in real-time using a black and white histogram visualization with bins arranged from left to right corresponding to low to high frequency ranges using a system based upon two Atmel Mega1284 microcontrollers. Our ECE 4760 final project was an audio spectrum analyzer that would display a histogram-style visualization of an audio signal.
#SPECTRUM FLICKERY CHACNNELS TV#
" An audio spectrum analyzer that displays a real-time histogram-style visualization of the frequency spectrum of an audio input signal on a TV screen."