(Removed) Recover symbol timing phase using squaring method
Squaring Timing Recovery has been removed. Use the Symbol Synchronizer block instead.
Timing Phase Recovery sublibrary of Synchronization
The Squaring Timing Recovery block recovers the symbol timing phase of the input signal using a squaring method. This feedforward, non-data-aided method is similar to the conventional squaring loop. This block is suitable for systems that use linear baseband modulation types such as pulse amplitude modulation (PAM), phase shift keying (PSK) modulation, and quadrature amplitude modulation (QAM).
Typically, the input to this block is the output of a receive filter that is
matched to the transmitting pulse shape. This block accepts a column vector
input signal of type
The input represents Symbols per frame symbols, using
Samples per symbol samples for each symbol.
Typically, Symbols per frame is approximately 100,
Samples per symbol is at least 4, and the input
signal is shaped using a raised cosine filter.
The block assumes that the phase offset is constant for all symbols in the entire input frame. If necessary, use the Buffer block to reorganize your data into frames over which the phase offset can be assumed constant. If the assumption of constant phase offset is valid, then a larger frame length yields a more accurate phase offset estimate.
The block estimates the phase offset for the symbols in each input frame and applies the estimate uniformly over the input frame. The block outputs signals containing one sample per symbol. Therefore, the size of each output equals the Symbols per frame parameter value. The outputs are as follows:
The output port labeled
Sym gives the
result of applying the phase estimate uniformly over the
input frame. This output is the signal value for each
symbol, which can be used for decision purposes.
The output port labeled
Ph gives the phase
estimate for each symbol in the input frame. All elements in
this output are the same nonnegative
real number less than the Samples per
symbol parameter value. Noninteger values
for the phase estimate correspond to interpolated values
that lie between two values of the input signal.
The number of symbols in each frame of the input signal.
The number of input samples that represent each symbol. This must be greater than 1.
This block uses a timing estimator that returns
as the normalized phase between -1/2 and 1/2, where x is the input vector, L is the Symbols per frame parameter and N is the Samples per symbol parameter.
 Oerder, M. and H. Myer, "Digital Filter and Square Timing Recovery," IEEE Transactions on Communications, Vol. COM-36, No. 5, May 1988, pp. 605-612.
 Mengali, Umberto and Aldo N. D'Andrea, Synchronization Techniques for Digital Receivers, New York, Plenum Press, 1997.
 Meyr, Heinrich, Marc Moeneclaey, and Stefan A. Fechtel, Digital Communication Receivers, Vol 2, New York, Wiley, 1998.