What is FSK modem?
Frequency-shift keying (FSK) is a method of transmitting digital signals using discrete signals. A modem converts the binary data from a computer to FSK for transmission over telephone lines, cables, optical fiber or wireless media.
What is FSK and where is FSK used?
The technology is used for communication systems such as telemetry, weather balloon radiosondes, caller ID, garage door openers, and low frequency radio transmission in the VLF and ELF bands. The simplest FSK is binary FSK (BFSK).
What device can be used for generation of FSK signal?
A VCO module is ideally suited for the generation of a continuous phase FSK signal, as shown in Figure 6.
What is the application of FSK?
Following are the typical applications of FSK modulation. It is used on voice grade lines for data rates upto 1200 bps. It is used for high frequency radio transmission from 3 to 30 MHz. It is also used in coaxial cable based LAN (Local Area Network) at higher frequencies.
How many carrier frequencies are used in FSK?
If frequency is the parameter chosen to be a function of the information signal, the modulation method is called frequency-shift keying (FSK). In the simplest form of FSK signaling, digital data is transmitted using one of two frequencies, whereby one frequency is used…
How many carrier frequencies are used in binary FSK?
FSK. In frequency shift keying, the carrier frequency is changed between discrete values. If only two frequencies are used then this will be called BFSK, for binary frequency shift keying. In this figure, the same data is represented, 1011.
What is the most commonly used demodulation technique for FSK?
The most used demodulation technique is the one using a PLL circuit (fig. 2). The FSK signal across the PLL input takes two frequency values. The error voltage supplied by the phase comparator follows such variations, and so, it constitutes the NRZ binary representation (high and low level) of the FSK input signal.
What frequency does the FSK utilize?
FSK, in the most basic case, represents a 1 (a mark) by one frequency and a 0 (a space) by another. These frequencies lie within the bandwidth of the transmission channel. On a V. 21, 300 bps, full-duplex modem the originator modem uses the frequency 980 Hz to represent a mark and 1180 Hz a space.
How is FSK bandwidth calculated?
The bandwidth of the periodic FSK signal is then 2f + 2B, with B the bandwidth of the baseband signal. The bit error probability can be shown to be pϵ = 1 2 e−E/2η , which under normal operating conditions corresponds to less than a 1dB penalty over coherent detection.
What is the frequency shift in FSK generator?
The FSK rate is the rate at which the output frequency “shifts” between the carrier frequency and the hop frequency using the internal FSK source. FSK rate (internal source): 125 µHz (33500 Series) or 250 µHz (33600 Series) up to 1 MHz, default 10 Hz. The FSK rate is ignored when the external FSK source is selected.
How FSK modulation and demodulation is done?
The FSK signal input is given to the two mixers with local oscillator circuits. These two are connected to two band pass filters. These combinations act as demodulators and the decision circuit chooses which output is more likely and selects it from any one of the detectors.
What is the PLL used for FSK demodulation?
A very useful application of the 565 PLL is as a FSK demodulator. In the 565 PLL the frequency shift is usually accomplished by driving a VCO with the binary data signal so that the two resulting frequencies correspond to the logic 0 and logic 1 states of the binary data signal.
What is the difference between FSK and 2fsk modulation?
As mentioned each symbol carries 1 bit of information. 2FSK is same as FSK modulation technique. Mathematically, 2FSK modulation can be expressed using following equations. Ac is carrier amplitude, Fc is carrier frequency and Δf is frequency deviation as mentioned in the table. Figure-2 depicts 4FSK modulator block.
What is an FSK modem used for?
V.21 is also used to transmit caller ID information over the phone line. An FSK modem is a digital communication system, so it transmits zeros and ones. In order to transmit messages in an alphabet, there must be a binary representation for each character in the alphabet.
What is a frequency shift keying modem?
The goal of this lab is to understand a simple modem, the Frequency Shift Keying (FSK) Modem, referred to by the International Telecommunications Union (I.T.U.) as V.21. The V.21 modem communicates 1’s and 0’s by sending either a 1650 Hz tone or a 1850 Hz tone, respectively, for 1/300 second.
How does FSK demodulator work?
In the FSK demodulator, data are demodulated from symbols after distinguishing different frequency deviation with respect to the reference carrier frequency used in the FSK modulator and FSK demodulator design. Figure-1 depicts 2FSK modulator block. As shown bits or binary digits (0 or 1) are used as inputs while symbols are generated as outputs.