Frequency Shift Keying (FSK) and signal amplitude are two different modulation techniques used in communication systems. The sensitivity of a modulation scheme refers to its ability to reliably detect and recover the transmitted information in the presence of noise and other impairments.
In general, FSK modulation is considered to be less sensitive to noise compared to amplitude-based modulation schemes, such as Amplitude Shift Keying (ASK) or Amplitude Modulation (AM). Here's why FSK is less sensitive:
Robustness against amplitude variations: FSK relies on varying the frequency of the carrier signal to convey information. Unlike amplitude-based schemes, FSK is less susceptible to changes in signal amplitude caused by noise or channel impairments. Since the amplitude variations do not affect the frequency demodulation process in FSK, it provides better immunity to amplitude-based noise sources.
Narrowband interference rejection: FSK is often implemented using narrowband filters to demodulate the desired signal. These filters help reject out-of-band interference, including noise and signals from other sources. By focusing on a specific frequency range, FSK can effectively reduce the impact of unwanted signals and improve its resilience against noise.
Improved signal-to-noise ratio (SNR) performance: The demodulation process in FSK involves frequency discrimination, which can be achieved using techniques like phase-locked loops (PLLs) or digital signal processing algorithms. These demodulation techniques can exploit the energy of the received signal more efficiently, resulting in improved SNR performance. By optimizing the use of available signal power, FSK can achieve better sensitivity than amplitude-based modulation schemes.
However, it's important to note that the sensitivity of a modulation scheme also depends on several other factors, such as the implementation quality, bandwidth utilization, and the specific characteristics of the communication channel. In certain scenarios, other modulation techniques may be more suitable based on the specific requirements and constraints of the communication system.