2 research outputs found
High-Precision Measurement of Sine and Pulse Reference Signals using Software-Defined Radio
This paper addresses simultaneous, high-precision measurement and analysis of
generic reference signals by using inexpensive commercial off-the-shelf
Software Defined Radio hardware. Sine reference signals are digitally
down-converted to baseband for the analysis of phase deviations. Hereby, we
compare the precision of the fixed-point hardware Digital Signal Processing
chain with a custom Single Instruction Multiple Data (SIMD) x86 floating-point
implementation. Pulse reference signals are analyzed by a software trigger that
precisely locates the time where the slope passes a certain threshold. The
measurement system is implemented and verified using the Universal Software
Radio Peripheral (USRP) N210 by Ettus Research LLC. Applying standard 10 MHz
and 1 PPS reference signals for testing, a measurement precision (standard
deviation) of 0.36 ps and 16.6 ps is obtained, respectively. In connection with
standard PC hardware, the system allows long-term acquisition and storage of
measurement data over several weeks. A comparison is given to the Dual Mixer
Time Difference (DMTD) and Time Interval Counter (TIC), which are
state-of-the-art measurement methods for sine and pulse signal analysis,
respectively. Furthermore, we show that our proposed USRP-based approach
outperforms measurements with a high-grade Digital Sampling Oscilloscope.Comment: 10 pages, 15 figures, and 4 table
Real World Verification Experiences from the Verisoft Email Client
This paper reports our experiences developing a completely verified email client. The formal specification of the email client includes all informal requirements and security goals. Compliance to the formal specification has been proven for the complete source code. The email client is part of project Verisoft, where pervasively verified systems are developed.