Meaning
Digital frequency shift keying represents an effective method for transmitting binary information over a wireless channel. Using 2-fsk modulation involves shifting the carrier frequency between two distinct values to denote logical zero and one. This technique avoids the amplitude sensitivity issues found in simpler methods.
A frequency deviation parameter defines the spacing between these tones.
Carrier Spacing
Tone separation determines the bandwidth required for successful transmission. Narrow deviations in 2-fsk modulation allow for high spectral density at the cost of sensitivity. Wide deviations improve the bit error rate by making the two states easier for the receiver to distinguish.
Hardware Complexity
Simplified circuitry makes this approach ideal for low power devices. Because 2-fsk modulation operates with a constant envelope, the power amplifier can run in a non-linear, high efficiency mode. This reduces the thermal load on the enclosure and extends battery life while simplifying the matching network between the chip and the antenna.
Designers prefer this modulation for sensors because it requires less processing overhead for frequency tracking than more complex phase-based systems.
Signal Integrity
Resistance to noise ensures reliable data delivery in crowded industrial bands. The demodulator in 2-fsk modulation tracks the frequency shift rather than the absolute signal level. Standard bit error rate curves show that this method maintains a stable link even as the signal nears the noise floor.
