MT MLSE Demapper (CPM)
- Updated2023-02-17
- 4 minute(s) read
MT MLSE Demapper (CPM)
Maps a CPM-modulated complex baseband waveform to an output bit stream using maximum likelihood sequence estimation (MLSE). The node expects the input complex waveform to be synchronized, in every aspect, to the receiver.
Inputs/Outputs
input complex waveform
The modulated complex baseband waveform data.
t0
Trigger (start) time of the Y array.
Default value: 0.0
dt
Time interval between data points in the Y array.
Default value: 1.0
Y
The complex-valued signal-only baseband modulated waveform. The real and imaginary parts of this complex data array correspond to the in-phase (I) and quadrature-phase (Q) data, respectively.
CPM system parameters
Parameter values defining the CPM system. Wire the CPM system parameters cluster from MT Generate CPM System Parameters (M) or MT Generate CPM System Parameters (map) to this cluster. Do not alter the values.
samples per symbol
An even, positive number of samples dedicated to each symbol. Multiply this value by the symbol rate to determine the sample rate.
Default value: 16
symbol map
A two-dimensional array of desired frequency deviations. Each column corresponds to a symbol, with the binary representation of the column index being the mapped bit-representation of the symbol. Each row corresponds to a modulation index in the order in which it appears in the modulation index, h(i) parameter of MT Generate CPM System Parameters (M) or MT Generate CPM System Parameters (map).
Default value: Empty array
pulse shaping filter coefficients
An ordered array containing the coefficients of the pulse-shaping filter used during the modulation of the received waveform.
CPM MLSE settings
CPM MLSE settings.
traceback depth
Number of trellis stages to trace back during the Viterbi decoding process. The output bit sequence is delayed, in time, by this amount with respect to the incoming waveform.
Default value: 15
h(i) start index
Index of the array of modulation indexes, h(i), corresponding to the modulation index of the first symbol. The node ignores this parameter if the reset? parameter is set to FALSE.
Default value: 0
block size
Length, in symbols, of a block of the received waveform, used during block-wise processing. At the beginning of each block, the node resets the Viterbi decoding process. Each block overlaps with the previous block for a number of symbols equal to traceback depth. To enable block-wise processing, set this value to a positive integer greater than the traceback depth.
Default value: -1
error in
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Default value: No error
reset?
A Boolean that determines whether the node continues demodulating using the previous iteration states.
| TRUE | Restarts the demodulator. The node resets on the first call and when reset? is set to TRUE. |
| FALSE | Continues demodulating using the previous iteration states. |
Default value: TRUE
output bit stream
The demapped information bit stream.
error out
Error information.
The node produces this output according to standard error behavior.