MSK Modulator Passband (Communications Blockset)

Modulate using the minimum shift keying method

Library

CPM, in Digital Passband sublibrary of Modulation

Description

The MSK Modulator Passband block modulates using the minimum shift keying method. The output is a passband representation of the modulated signal.

The input must be sample-based. If the Input type parameter is Bit, then the input must be a vector of length log₂(M), containing values of 0 and 1. If the Input type parameter is Integer, then the input must be a scalar containing values of 1 and -1.

Parameters Specific to Passband Simulation

Passband simulation uses a carrier signal. The Carrier frequency and Carrier initial phase parameters specify the frequency and initial phase, respectively, of the carrier signal. The Symbol period parameter must equal the sample time of the input signal, while the Output sample time parameter determines the sample time of the output signal.

This block uses a baseband representation of the modulated signal as an intermediate result during internal computations. The Baseband samples per symbol parameter indicates how many baseband samples correspond to each integer or binary word in the input, before the block converts them to a passband output.

The timing-related parameters must satisfy these relationships:

Symbol period > (Carrier frequency)^-1

Output sample time < [2*Carrier frequency + 2/(Symbol period)]^-1

Symbol period = K*Output sample time*Baseband samples per symbol for some integer K

Furthermore, Carrier frequency is typically much larger than the highest frequency of the unmodulated signal.

Dialog Box

Input type: Indicates whether the input consists of bipolar or binary values.
Symbol period (s): The symbol period, which must equal the sample time of the input.
Baseband samples per symbol: The number of baseband samples that correspond to each integer or binary word in the input, before the block converts them to a passband output.
Carrier frequency (Hz): The frequency of the carrier.
Carrier initial phase (rad): The initial phase of the carrier in radians.
Output sample time: The sample time of the output signal.

Pair Block

MSK Demodulator Passband

See Also

MSK Modulator Baseband

References

Anderson, John B., Tor Aulin, and Carl-Erik Sundberg. Digital Phase Modulation. New York: Plenum Press, 1986.

MSK Modulator Baseband Mu-Law Compressor