FSK modulation is a digital modulation method. FSK, or frequency shift keying modulation, is a modulation technique commonly used in digital communication. It uses the frequency change of the carrier to transmit digital information. In FSK modulation, the logical states "1" and "0" in the binary data correspond to different carrier frequencies. Specifically, it achieves the transmission of digital information by changing the frequency of the carrier to represent different digital signal states.
FSK modulation (2FSK is binary digital frequency modulation),The frequency of the carrier is used to transmit digital information, that is, the frequency of the carrier is controlled by the digital information transmitted. The 2FSK signal is the modulated waveform of the symbol "0" corresponding to the carrier frequency f1, and the symbol "1" corresponding to the carrier frequency f2 (a different carrier frequency from f1), and the change between f1 and f2 is instantaneous.
In the field of information transmission, FSK, or frequency shift keying, is a long-established and widely used modulation method. It has the advantages of simple implementation, good anti-noise and anti-attenuation performance, especially suitable for medium and low speed data transmission. How FSK worksIt is the use of digital signals to modulate the carrier frequency, such as 2FSK, which can be regarded as the superposition of ASK signals of two different carrier frequencies.
Frequency Shift Keying (FSK) modulation is a widely used digital signal modulation technique that carries data by changing the frequency of the signal, and is a simple and reliable modulation technique for transmitting digital signals. The basic principle of FSK modulation is to convert digital signals (that is, 0 and 1) into different frequencies.
ASK signal Modulation signal: single-stage non-return-to-zero rectangle4000-14350khz. 18068-18168khz. 21000-21450 KHZ. 24890-24990khz.
2, China's amateur radio operators have a clear range of frequencies, according to the "People's Republic of China Radio frequency Division Regulations", these frequencies include: 1800-2000khz, 3500-3900khz, 7000-7200khz, 10100-10150khz (minor), 14000-14350khz, 18068-18168kHz, 21000-21450khz and 24890-24990khz.
3, 4 1000 to 1350 MHz: This is the 20 meter amateur radio band, the low end of 100kHz is used for CW (constant amplitude) and RTTY (teletype), and the rest of the frequencies use USB (upper sideband) mode (HAM cannot use SSB (single sideband) below 14150 kHz in the United States.
4, frequency as a national resource, subject to strictThe regulation of lattice. Nevertheless, certain bands are open to amateurs, such as 430-440 MHZ. A radio operating certificate must be obtained before using these bands. Having a radio license is a requirement to operate an amateur station. Public unlicensed walkie-talkies in the 409MHz band can be used without any restrictions.
5, the following are some common areas and the corresponding amateur radio frequency table: * Beijing: 43500-43500, 1405 147140500, 147500, 14650-14750-14575-141714100 Direct frequency 43750-43750, 435M direct frequency 140M direct frequency.
MSK is a kind of modulation that improves the FSK signal so that its phase is always continuously unchanged. Minimum frequency shift keying is also known as Fast Frequency shift keying (FFSK). Here "minimum" means that the orthogonal signal can be obtained with the smallest modulation index (i.e. 0.5); And "fast" means that for a given frequency band, it can outperform PSK transmits higher bit rates.
Difference: In FSK mode, the phase is usually discontinuous. MSK is a type of modulation that keeps its phase continuously constant at all times. Connection: MSK is an improvement of FSK signal based on FSK. In FSK mode, the frequency of adjacent code elements is unchanged or jumps to a fixed value. Between two adjacent frequency-hopping elements, the phase is usually discontinuous.
-MSK modulation: The spectrum of MSK modulation is narrow, and the adjacent channel leakage is low. This makes MSK modulation in terms of high frequency band utilization and anti-interference abilityHave an advantage. - FSK modulation: The spectrum of FSK modulation is wide and the adjacent channel leakage is high. This can lead to lower band utilization, but FSK modulation has advantages in terms of simplicity of implementation and equipment cost. Connection: Both MSK modulation and FSK modulation are digital modulation techniques used to transmit digital signals in a channel.
Difference: FSK: frequency shift keying, the phase is usually discontinuous; MSK: Minimum frequency shift keying, a type of modulation whose phase is always continuously unchanged.