The effects of MR induced non-linearities on channel performance

Chopra, K. L.; Nix, L.; Taberski, K.D.

doi:10.1109/20.334034

Cited by 16 publications

(11 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To estimate the impact of GMR nonlinearity on BER performance, the model of the transfer curve of GMR [ ] approximates a hyperbolic-tangent curve (1) Normalized field " " is defined as the applied field divided the maximum applied field Happ/Hmax . A positive saturated parameter and a negative saturated parameter approach linear as parameters " " and " " go to 0.…”

Section: A Channel Simulationmentioning

confidence: 99%

Characterization of GMR Nonlinear Response and the Impact on BER in Perpendicular Magnetic Recording

et al. 2004

View full text Add to dashboard Cite

The giant magnetoresistive (GMR) reader nonlinear response in perpendicular magnetic recording should be characterized and studied for the impact on bit-error-rate (BER) performance, because a waveform of perpendicular recording is influenced by GMR nonlinearity differently from longitudinal recording. In this study, the read/write characteristics and BER performance under the influence of GMR nonlinearity were investigated. For a GMR saturation parameter, the amplitude ratio of the fifth harmonic spectrum of isolated patterns to same spectrum of di-bit pattern was measured. This saturation parameter is a good indicator to estimate GMR saturation. GMR asymmetry has a different impact on BER performance from GMR saturation. The raw isolated waveform of perpendicular recording is inappropriate to estimate GMR asymmetry because it does not indicate an accurate dc-ground level with the low-frequency cutoff channel. A specific test patterns which can provide dc-ground level, was found. The measured asymmetry of this test pattern correlates closely with the asymmetry of measured GMR transfer curves. The peak shift of a differential waveform is also a good indicator to estimate GMR asymmetry. Signal processing simulation and some measurement results showed BER performance is influenced by GMR nonlinear response. The impact of GMR nonlinearity on BER depends on their feature. GMR asymmetry has a strong correlation with BER performance.

show abstract

Section: A Channel Simulationmentioning

confidence: 99%

Characterization of GMR Nonlinear Response and the Impact on BER in Perpendicular Magnetic Recording

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Nonlinear readback has been shown to degrade the performance of partial-response maximum-likelihood (PRML) channels [TI, [8]. In this section we examine the performance of PRML detection on the linearized channel.…”

Section: E Linearizing the Channel For Prml Detectionmentioning

confidence: 99%

Linearizing the read process for write nonlinearity measurements

1997

View full text Add to dashboard Cite

Many standard tests for write nonlinearities such as nonlinear transition shift and partial erasure assume a linear read process. Nonlinear effects from readback with a magnetoresistive head can make the results of these tests difficult to interpret. We show how a polynomial can be used to approximate the inverse transfer function and thus linearize the read channel. Write nonlinearities can be measured more easily by performing tests on the linearized channel. We also show how linearizing the channel for PRML detection is limited by amplification of noise over parts of the inverse transfer curve with high differential gain.

show abstract

“…The difference in the magnitudes of the positive and negative pulse amplitudes divided by the peak-to-peak amplitude is known as amplitude asymmetry (A.A.). It is known that A.A. degrades the performance (mean-square error or MSE, and' bit-error rate or BER) of partial response channels [1, 2,3]. However, it has proven difficult to directly measure the impact of A.A. on such channels; variations in other parametrics (for example, amplitude, nonlinear transition shift or NLTS) from one head to another also affect the channel performance.…”

Section: Introductionmentioning

confidence: 99%

Impact of amplitude asymmetry on partial response (PR4 and EPR4) channels

Stupp

1999

IEEE Trans. Magn.

View full text Add to dashboard Cite

The dependence of MSE and marginalized BER on. amplitude asymmetry for two partial response channels is reported. To eliminate the impact of variations in other head parameters, we varied the bias point of a given head using an external magnetic field. We find that the MSE degrades continuously as the magnitude of the amplitude asymmetry is increased; the marginalized BER is at most weakly dependant on amplitude asymmetry for magnitudes less than 15 %. At larger magnitudes the channel performance is more severely impacted. Finally, we were able to simulate these results using a simplified model of the read channel.

show abstract

The effects of MR induced non-linearities on channel performance

Cited by 16 publications

References 5 publications

Characterization of GMR Nonlinear Response and the Impact on BER in Perpendicular Magnetic Recording

Characterization of GMR Nonlinear Response and the Impact on BER in Perpendicular Magnetic Recording

Linearizing the read process for write nonlinearity measurements

Impact of amplitude asymmetry on partial response (PR4 and EPR4) channels

Contact Info

Product

Resources

About