Chuang, "Reduction of peak-to average power ratio of OFDM signals with companding
To restore the original coefficient z at the receiving side, the values of TL, TR, the compressed location map, the companding
error e, and the threshold matrix T, called overhead data, should be embedded into the cover image along with the pure payload (namely the watermarking data).
Figures 6a through 6c compare the BW efficiency performance of the DWT & DCT systems with and without companding
to that of with exponential transform.
The rest of the paper is organized as follows: Section II describes the companding
system with embedded G.711 quantizer.
By using the proposed companding
transform in Section 3, the MCM signals are companded before they are converted into analog waveforms and amplified by the high power amplifier (HPA).
Recently, an iterative companding
transform and filtering (ICTF) scheme  has been proposed in which linear and piecewise linear transforms have been selected due to their low implementation complexity.
Tsividis, "Externally linear, time-invariant systems and their application to companding
signal processors", IEEE Trans.
In this paper, a new adaptive companding
scheme is proposed along with its design methodology.
Tihung, "Reduction of peak-to-average power ratio of OFDM systems using a companding
technique," IEEE Transaction on Broadcasting, vol.
We choose to use the logarithmic companding
quantizer with u compression law within DPCM system, due to its robustness.
The problem that generaly occurs in designing quantizers, including [mu]-law companding
quantizers, is how to provide the simple manner of determining the support region threshold of the quntizer to minimize distortion introduced in the quantization process.
Samuelsson, "Multidimensional Companding
Quantization of the Gaussian Source", IEEE Trans.