GPS	Global positioning system
3D	Three-dimensional
USG	Ultrasonic sound guide
ADC	Analog-to-digital converter
LPF	Low pass filter
DAC	Digital-to-analog converter
FPU	Floating-point unit
I2S	Inter-IC sound
MCK	Master clock
CK	Serial clock
WS	Word select clock
SD	Serial data
PDM	Pulse density modulation
PCM	Pulse coded modulation
DMA	Direct memory access
FIFO	First-in first-out
DTFT	Discrete-time Fourier transform
FIR	Finite impulse response
SP	Single precision
CDC	Centers for disease control and prevention
SNR	Signal-to-noise ratio