A new circuit technique based on pass-gate logic with dynamic supply-voltage and clock-frequency control is proposed for a low-power motion-vector detection VLSI processor. Since the pass-gate logic style has potential advantages that have small equivalent stray capacitance and small number of short-circuit paths, its circuit implementation makes it possible to reduce the power dissipation with maintaining high-speed switching capability. In case the calculation result is obtained on the way of calculation steps, additional power saving is also achieved by combining the pass-gate logic circuitry with a mechanism that dynamically scales down the supply voltage and the clock frequency while maintaining the calculation throughput. As a typical example, a sum of absolute differences (SAD) unit in a motion-vector detection VLSI processor is implemented and its efficiency in power saving is demonstrated.

A novel method for measuring microwave reflection coefficients without the open and load standards is proposed. In this method, a single probe is inserted into an air line and the output wave is detected by a vector detector. Offset shorts are used for the calibration. The measurement system is constructed using 7 mm coaxial line and APC7 connectors. The result of the measurement in the frequency range 1-9 GHz shows the possibility of the proposed method. All the major systematic errors can be estimated from the data that is easily obtainable.