MT Align To Ideal Symbols (Offset PSK)
- Updated2023-02-17
- 5 minute(s) read
MT Align To Ideal Symbols (Offset PSK)
Aligns the first sample of the input complex waveform to the ideal symbol timing instant for an offset PSK (OPSK) modulation scheme. This node returns an output complex waveform (offset removed) with the 1/2 symbol I/Q offset removed. Wire the output complex waveform (offset removed) to MT Decimate Oversampled Waveform to obtain the demodulated soft symbol decisions.
Inputs/Outputs
input complex waveform
The continuous-time samples of the modulated complex baseband waveform data. Wire the output complex waveform returned from MT Matched Filter to this parameter.
- The sample rate of the input complex waveform must be an even integer multiple of the expected symbol rate. Use MT Resample (Complex Cluster) to adjust the sampling rate of the input complex waveform if necessary.
- An appropriate matched filter must be previously applied to the input complex waveform using MT Apply Matched Filter.
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.
matched filter coefficients
An ordered array containing coefficients for the matched filter that has been applied to the input complex waveform. Wire the matched filter coefficients parameter of MT Generate Filter Coefficients to this parameter. Ensure that the value of the samples per symbol parameter in this node matches the matched samples per symbol value used to generate these filter coefficients.
samples per symbol
Number of samples per information symbol in the input complex waveform.
Default value: 16
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 to align the input complex waveform to ideal symbol timing instants using the previous iteration states.
| TRUE | Resets the node. The node resets on the first call and when reset? is set to TRUE. |
| FALSE | Continues to align the input complex waveform to ideal symbol timing instants using the previous iteration states. |
Default value: TRUE
output complex waveform
The symbol-time-aligned I/Q baseband waveform. Wire this parameter to MT Decimate Oversampled Waveform followed by MT Map Symbols to Bits to obtain the recovered bits corresponding to the modulated waveform.
t0
Trigger (start) time of the Y array.
Default value: 0
dt
Time interval between data points in the Y array. The reciprocal of this value is equal to the system sample rate.
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.
output complex waveform offset removed
The matched-filtered continuous-time I/Q baseband waveform with the 1/2 symbol I/Q timing offset removed. Wire this parameter to MT Decimate Oversampled Waveform followed by MT Map Symbols to Bits to obtain the recovered bits corresponding to this offset-removed symbol-time-aligned waveform.
t0
Trigger (start) time of the Y array.
Default value: 0
dt
Time interval between data points in the Y array. The reciprocal of this value is equal to the system sample rate.
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.
waveform alignment offset
Location of the ideal symbol timing instant, in samples, relative to the beginning of the input complex waveform. This offset was applied to the output complex waveform. Multiply this value by the dt element of the input complex waveform to calculate the location of the ideal symbol timing instant in seconds.
error out
Error information.
The node produces this output according to standard error behavior.