MT Generate PSK Synchronization Parameters (number array)
- Updated2023-02-17
- 6 minute(s) read
MT Generate PSK Synchronization Parameters (number array)
Generates synchronization parameters for PSK demodulation using a synchronization sequence defined by a sync numbers array in which each number represents a group of bits. The generated synchronization parameters cluster avoids phase ambiguity at the demodulator, thus allowing recovery of the actual message bits.
Inputs/Outputs
PSK system parameters
Parameter values defining the PSK system. Wire the PSK system parameters cluster returned by MT Generate PSK System Parameters (M) or MT Generate PSK System Parameters (map) to this cluster. Do not alter the values.
samples per symbol
An even number of samples dedicated to each symbol. Multiply this value by the symbol rate to determine the sample rate.
Default value: 16
symbol map
An ordered array that maps each Boolean symbol to its desired coordinates in the complex plane. The number of PSK states in the array must be 2N, where N is the number of bits per symbol.
differential PSK
Status of the differential PSK.
| disable |
Disables bit sequence encoding. |
| enable |
Enables bit sequence encoding. |
Default value: enable
PSK type
Type of PSK modulation.
| normal |
Sets the modulation type to regular PSK. |
| shifted |
Rotates the constellation by /M each symbol. |
| offset |
Sets the modulation type to offset quadrature phase-shift keying (OQPSK). This modulation scheme is a form of phase-shift keying in which four different phase angles are used. This scheme is sometimes referred to as staggered quadrature phase-shift keying (SQPSK). For offset PSK, the ideal symbol timing for Q is offset by 1/2 of a symbol period from the ideal symbol timing for I. offset is currently only supported for M= 4. |
Default value: normal
sync numbers
An array of synchronization numbers in which the binary representation of each number is used to generate the sync bit array. By default, the internal conversion of each sync number into the corresponding synchronization bit sequence is performed with the most significant bit first (left-aligned) approach.
For example, if you specify a preamble word of 1111 1111 1111 1110 for symbol synchronization, you can specify sync numbers as an array with a single element xFFFE. Specify the bits per sync number value to be 16. You can also specify sync numbers as an array of two elements (xFF and xFE), and specify the bits per sync number value as 8. For reliable symbol synchronization, specify an array of length (10 × bits per symbol).
Default value: 0
bits per sync number
Number of bits corresponding to each sync number in the sync numbers array.
Default value: 32
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
expected sync location
The expected location of the synchronization parameters in symbols. Set this value to -1 to search the entire waveform for the synchronization symbols.
Default value: -1
sync location uncertainty
Number of symbols before or after the expected sync location where the first symbol of the sync sequence may be located. The node ignores this parameter if the expected sync location parameter is set to -1.
Default value: 10
sync indent
Distance that the sync sequence is indented into the information block.
The distance is the number of demodulated symbols preceding the sync sequence. For example, a value of 10 indicates that the output bit stream consists of 10 data symbols, followed by the sync sequence, followed by the remaining data symbols.
Default value: 0
PSK synchronization parameters
Synchronization parameters to pass to the demodulation node.
If the synchronization parameter passed to the demodulation node is left empty, the constellation of the demodulated waveform has a 90° carrier phase ambiguity for two-dimensional modulation schemes (QAM, QPSK, and higher order PSK) and a 180° carrier phase ambiguity for one-dimensional modulation schemes (PAM/ASK/BPSK).
expected sync location
The expected location of the first symbol of the sync sequence.
This value is an index to the input complex waveform. A value of -1 searches the entire input complex waveform and ignores the sync location uncertainty parameter.
sync sequence
The mapped symbol array from the specified synchronization bits or synchronization numbers.
sync location uncertainty
Number of symbols before or after the expected sync location where the first symbol of the sync sequence may be located. The node ignores this parameter if the expected sync location parameter is set to -1.
Default value: 10
sync indent
Distance that the sync sequence is indented into the information block.
The distance is the number of demodulated symbols preceding the sync sequence. For example, a value of 10 indicates that the output bit stream consists of 10 data symbols, followed by the sync sequence, followed by the remaining data symbols.
Default value: 0
error out
Error information.
The node produces this output according to standard error behavior.