MT Align to Ideal Symbols (Generic)
- Updated2023-02-17
- 4 minute(s) read
MT Align to Ideal Symbols (Generic)
Locates the first occurrence of the ideal symbol timing instant in the matched filtered input complex waveform, then applies phase-continuous resampling to align the first sample of the input complex waveform to the ideal symbol timing instant for PAM, ASK, QAM, and non-offset PSK modulation schemes. The returned waveform is symbol-time aligned such that its first sample corresponds to the optimal (ideal) symbol instant.
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.
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.
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.