A Simple PLL-Based True Random Number Generator for Embedded Digital Systems

The paper presents a simple True Random Number Generator (TRNG) which can be embedded in digital Application Specific Integrated Circuits (ASICs) and Field Programmable Logic Devices (FPLDs). As a source of randomness, it uses on-chip noise generated in the internal analog Phase-Locked Loop (PLL) circuitry. In contrast to traditionally used free-running oscillators, it uses a novel method of randomness extraction based on two rationally related synthesized clock signals. The generator has been developed for embedded cryptographic applications, where it significantly increases the system security, but it can be used in a wide range of other applications. The functionality of the proposed solution is demonstrated for the Altera Apex FPLD family, but the same principle can be used for all recent ASICs or FPLDs that include an on-chip reconfigurable analog PLL. The quality of the TRNG output is confirmed by applying special DIEHARD and NIST statistical tests, which pass even for high output bit-rates of several hundreds of Kbits/s

Integrated multipoint-laser endoscopic airway measurements by transoral approach

Objectives: Optical and technical characteristics usually do not allow objective endoscopic distance measurements. So far no standardized method for endoscopic distance measurement is available. The aim of this study was to evaluate the feasibility and accuracy of transoral airway measurements with a multipoint-laser endoscope. Methods: The semirigid endoscope includes a multipoint laser measurement system that projects 49 laser points (wavelength 639 nm, power < 5mW) into the optical axis of the endoscopic view. Distances, areas, and depths can be measured in real-time. Transoral endoscopic airway measurements were performed on nine human cadavers, which were correlated with CT measurements. Results: The preliminary experiment showed an optimum distance between the endoscope tip and the object of 5 to 6 cm. There was a mean measurement error of 3.26% ± 2.53%. A Spearman correlation coefficient of 0.95