08. Frequency Shift Keying

Frequency Shift Keying (FSK)

The frequency of the carrier signal is varied to represent binary 1 or 0.

TRUE

[TRUE or FALSE] In FSK, while the frequency changes, both peak amplitude and phase remain constant.

constant

In FSK, the frequency of the signal during each bit duration is ______, and its value depends on the bit (0 or 1).

Frequency Shift Keying (FSK)

It is a form of constant-amplitude angle modulation similar to standard frequency modulation (FM) except the modulating signal is a binary signal that varies between two discrete voltage levels rather than a continuously changing analog waveform.

2 carrier frequencies

One way to think about binary FSK (BFSK) is to consider ___.

TRUE

[TRUE or FALSE] ASK is very simple.

TRUE

[TRUE or FALSE] FSK needs a larger bandwidth than ASK.

TRUE

[TRUE or FALSE] FSK has more error resilience than AM.

f_b = 2B log₂ M

Formula for bit rate

B = f_b / N

Formula for solving the minimum bandwidth

baud = f_b / N

Formula for solving the baud rate

baud = f_b / N; N = 1

Formula for solving the baud rate of FSK

TRUE

[TRUE or FALSE] In digital modulation, the baud and the ideal minimum Nyquist bandwidth have the same value and are equal to thw bit rate divided by the number of bits encoded. This statement holds true for all forms of digital modulation except FSK.

Minimum bandwidth for FSK

mark frequency

f_m means?

space frequency

f_s means?

1

binary input of f_m (mark frequency)

0

binary input of f_s (space frequency)

NRZ binary input

What kind of input does an FSK modulator have?

FSK Modulator (VCO)

Main component used in FSK modulator

Voltage Controlled Oscillator

VCO meaning

phase comparator, VCO, amp

Components used in FSK demodulator

PLL-FSK demodulator

Continuous-Phase Frequency Shift Keying (CP-FSK)

It is binary FSK except the mark and space frequencies are synchronized with the input binary bit rate.

Continuous-Phase Frequency Shift Keying (CP-FSK)

It ensures a smooth phase transition in the analog output signal when it changes from a mark to a space frequency or vice versa.

Continuous-Phase Frequency Shift Keying (CP-FSK)

Better bit-error performance than conventional bimary FSK for a given SNR.