Minimum shift keying modulation

Minimum Shift Key Modulation is another type of digital modulation technique used to convert a digital signal into analog signals. It is also called Minimum-shift keying (MSK) or Advance Frequency Shift Keying because it is a type of continuous-phase frequency-shift keying.

1. What is minimum shift keying technique?
2. What is the minimum difference in frequency in MSK?
3. How does MSK modulation work?
4. Why MSK is better than QPSK?

What is minimum shift keying technique?

The minimum-shift keying (MSK) scheme is used in GSM, a pioneer and a widely-used digital cellular mobile system. MSK can be viewed as either a special case of binary continuous-phase frequency-shift keying (CPFSK) or a special case of OQPSK.

What is the minimum difference in frequency in MSK?

This arises as a result of the unique factor of MSK that the frequency difference between the logical one and logical zero states is always equal to half the data rate. This can be expressed in terms of the modulation index, and it is always equal to 0.5.

How does MSK modulation work?

The MSK modulation is a constant envelope signal with continuous phase that results from modulating the instantaneous frequency with rectangular pulses. MSK is considered to be a special case of Offset QPSK (OQPSK) with half sinusoidal pulse weighting rather than rectangular.

Why MSK is better than QPSK?

Overall, for direct detection systems, MSK has an advantage over QPSK because the compensation of nonlinearities on the receiver side is not possible and MSK performs better under these circumstances [2]. Furthermore the receiver for MSK is easier to implement. For coherent detection, this advantage is reduced.