Three-Dimensional EXIT Chart Analysis of Iterative Detection Aided Coded Modulation Schemes

The iterative convergence of iteratively detected coded modulation schemes having different block lengths, decoding complexity and an unequal error protection capability is studied, when communicating over AWGNchannels using 8PSK modulation. More specifically, the coded modulation schemes investigated include Multilevel Coding (MLC), Trellis Coded Modulation (TCM), Turbo Trellis Coded Modulation (TTCM), Bit-Interleaved Coded Modulation (BICM) as well as Bit-Interleaved Coded Modulation employing Iterative Decoding (BICM-ID). A novel three dimensional EXIT chart was introduced for studying the iterative convergence behaviour of the Multistage Decoding (MSD) scheme used in MLC

Multiple range imaging camera operation with minimal performance impact

Time-of-flight range imaging cameras operate by illuminating a scene with amplitude modulated light and measuring the phase shift of the modulation envelope between the emitted and reflected light. Object distance can then be calculated from this phase measurement. This approach does not work in multiple camera environments as the measured phase is corrupted by the illumination from other cameras. To minimize inaccuracies in multiple camera environments, replacing the traditional cyclic modulation with pseudo-noise amplitude modulation has been previously demonstrated. However, this technique effectively reduced the modulation frequency, therefore decreasing the distance measurement precision (which has a proportional relationship with the modulation frequency). A new modulation scheme using maximum length pseudo-random sequences binary phase encoded onto the existing cyclic amplitude modulation, is presented. The effective modulation frequency therefore remains unchanged, providing range measurements with high precision. The effectiveness of the new modulation scheme was verified using a custom time-of-flight camera based on the PMD19-K2 range imaging sensor. The new pseudo-noise modulation has no significant performance decrease in a single camera environment. In a two camera environment, the precision is only reduced by the increased photon shot noise from the second illumination source

Switching management in couplers with biharmonic longitudinal modulation of refractive index

We address light propagation in couplers with longitudinal biharmonic modulation of refractive index in neighboring channels. While simplest single-frequency out-of-phase modulation allows suppression of coupling for strictly defined set of resonant frequencies, the addition of modulation on multiple frequency dramatically modifies the structure of resonances. Thus, additional modulation on double frequency may suppress primary resonance, while modulation on triple frequency causes fusion of primary and secondary resonances.Comment: 13 pages, 4 figures, to appear in Optics Letter

Frequency modulation of spin torque oscillator pairs

The current controlled modulation of nano-contact based spin torque oscillator (STO) pairs is studied in both the synchronized and non-synchronized states. The synchronized state shows a well behaved modulation and demonstrates robust mutual locking even under strong modulation. The power distribution of the modulation sidebands can be quantitatively described by assuming a single oscillator model. However, in the non-synchronized state, the modulation sidebands are not well described by the model, indicating interactions between the two individual nano-contact STOs. These findings are promising for potential applications requiring the modulation of large synchronized STO arrays