Does comm.MSKDemodulator filter its input before demodulation?

Hi

Documentation states 1: This object implements the algorithm, inputs, and outputs described on the MSK Demodulator Baseband block reference page. The object properties correspond to the block parameters.

Documentation states 2: Note: The modulation and demodulation functions do not perform pulse shaping or filtering. See Combine Pulse Shaping and Filtering with Modulation for more information about filtering.

If I understand the documentation the answere to me question should be "No filtering".

Running a simulation with multiple samples per symbol and an AWGN channel between MSK modulator and MSK demodultor gives some odd results. With Simulink using the MSK Demodulator Baseband block and 32 samples per symbol, a low pass filter removing "out of band" noise reduces the error rate (as expected). "No filtering" still my conclusion. M code test 1: Running the same simulation using m code and comm.MSKDemodulator object the noise filter has no effect.... indicates internal filtering in comm.MSKDemodulator M code test 2: Running without the filter, reducing samples per symbol, error rate unchanged if AWGN channel is specified with Eb/N0 .... indicates internal filtering in comm.MSKDemodulator M code test 3: Running without the filter, reducing samples per symbol, error rate increase if AWGN channel is specified with SNR .... indicates internal filtering in comm.MSKDemodulator

Is there an internal filter? If so, what kind?

Regards pk