hesela.devPartial-response target
A partial-response target specifies the desired sampled channel response, including controlled contributions from neighboring symbols, used by an equalizer and sequence detector.
With D denoting one channel-symbol delay, PR4 is 1 - D^2 and EPR4 is 1 + D - D^2 - D^3 [1]. The target describes signal-amplitude arithmetic, not binary XOR.
Umemoto's PR5 proposal uses -1 + 2D^2 - D^4 for a particular single-layer perpendicular recording configuration [2]. These targets are distinct responses within this concept, not aliases for interchangeable implementations.
A target alone does not specify the noise model, detector, constrained code or error-correction stage. State counts must name their trellis and sampling convention.
Relations
- related
- PRML detection, Noise-predictive maximum-likelihood detection, Intersymbol interference, Perpendicular magnetic recording (PMR)