Information Sequence Processing with FSK Modulation System

In this system, the information sequence first undergoes Frequency Shift Keying (FSK) modulation, typically implemented using digital oscillators generating distinct frequencies for binary symbols. The modulated signal then passes through a low-pass filter with 25kHz cutoff frequency, which restricts the signal bandwidth using convolution operations with filter coefficients. This filtered signal is upconverted by a mixer to higher transmission frequencies through multiplication with carrier waveforms. At the receiver, synchronized frequency-hopping signals perform downconversion (de-hopping processing occurs here) using correlation techniques to align with transmitter timing. The lower sideband is extracted through envelope detection or Hilbert transform methods, followed by FSK demodulation employing frequency discrimination algorithms like phase-locked loops or Fast Fourier Transform (FFT) analysis. This processing chain enables reliable information transmission and decoding through coordinated modulation and synchronization mechanisms.