Tackling the terrorists: the experience of internment without trial in Northern Ireland

In August 1971, the devolved Stormont administration in Northern Ireland introduced internment without trial of those suspected of involvement in IRA terrorism. Ever since, the policy has been regarded as an abject failure. This article will reassess many of the key questions about internment: why did the Northern Ireland government introduce it when it did? Why did the Westminster government agree to a measure without parallel in British peacetime history? Why did it fail, when it had worked before? Was internment always doomed, or only because it was badly implemented? What was the alternative? How does the liberal democratic state defend itself against violent subversion without itself resorting to brutality and violence? This article is based on archival research in Great Britain, Northern Ireland and the Republic of Ireland, and on interviews with former internees, politicians and civil servants, and former members of the security forces. It suggests that internment was a relatively humane and honest policy and might, in different circumstances, have spared Northern Ireland thirty years of murder and mayhem.

Variable centre frequency resonator based bandpass Σ-Δ modulator

A novel resonator-based bandpass Σ-Δ modulator with an in-built variable centre frequency feature is presented. This structure is designed by analytically determining and subsequently verifying through behavioural level simulations the necessary compensation hardware to be placed in the feedback to ensure stability and good dynamic range performance.

Application of fractional delay filters to tune the centre frequency location of single-band sigma-delta modulators

This paper presents a novel technique for the design of narrow-band sigma-delta modulators with an embedded tunable centre frequency mechanism. This method demonstrates that the use of sum filters combined with a fractional delayer provide the flexibility of tuning the noise shaping band for any desired variable centre frequency input signal.

Increasing the variability of centre frequency locations in multiple-band sigma-delta modulators via the use of fractional delay filters

This paper presents the design analysis of novel tunable narrow-band bandpass sigma-delta modulators, that can achieve concurrent multiple noise-shaping for multi-tone input signals. This approach utilises conventional comb filters in conjunction with FIR, or allpass IIR fractional delay filters, to deliver the desired nulls for the quantisation noise transfer function. Detailed simulation results show that FIR fractional delay comb filter based sigma-delta modulators tune accurately to most centre frequencies, but suffer from degraded resolution at frequencies close to Nyquist. However, superior accuracies are obtained from their allpass IIR fractional delay counterpart at the expense of a slight shift in noise-shaping bands at very high frequencies.

Tunable centre frequency resonator based bandpass Σ-Δ modulators

This paper presents a methodology for the design of oversampled narrow-band single-loop and multi-stage resonator-based bandpass Σ-Δ modulators that can accommodate different passband centre to sampling frequency ratios. These tunable bandpass configurations are designed by analytically determining the required compensation hardware to deliver good resolution. Thorough simulations demonstrate that comparatively superior in-band signal-to-noise ratios (SNRs) and dynamic ranges (DRs) are attributed to the inclusion of appropriate feedforward and feedback compensators within these structures.