This routine performs a 1-D Periodic Orthogonal Wavelet decomposition. It also performs the row decomposition component of a 2-D wavelet transform. An input signal x[n] is low pass and high pass filtered and the resulting signals decimated by factor of two. This results in a reference signal r1[n] which is the decimated output obtained by dropping the odd samples of the low pass filter output and a detail signal d[n] obtained by dropping the odd samples of the highpass filter output. A circular convolution algorithm is implemented and hence the wavelet transform is periodic. The reference signal and the detail signal are each half the size of the original signal.