Abstract: A pseudo-differential amplifier circuit 1 is constructed from two equivalent amplifiers 2 and 3 that amplify a pair of input signals without using a differential pair. This pseudo-differential amplifier circuit 1 is used in an arithmetic unit in each of the A-D converter circuits AD1 through ADm in a parallel pipeline A-D converter 10.

Abstract: An image sensing element for providing a series of voltage signals corresponding to a two-dimensional image, a two-dimensional analog DCT (discrete cosine transform) circuit for performing a two-dimensional DCT on the voltage signal series from the image sensing element in pixel blocks, and a quantization circuit for quantizing a result of the DCT are provided. The two-dimensional analog DCT circuit is formed of a row of analog sum-of-products arithmetic units for one-dimensional DCT and an analog memory array for matrix transposition. The quantization circuit converts a voltage representing a result of the DCT carried out by the two-dimensional analog DCT circuit into a digital value according to a given quantization coefficient Q=2.sup.N .multidot.S(1.ltoreq.S<2) wherein a voltage S.multidot.Vref that is S times greater than a fixed voltage Vref serves as a reference voltage, and performs a process of right-shifting the digital value N bits in order to provide a quantized digital value.

Abstract: A semiconductor pressure sensor comprises a diaphragm formed by anisotropic etching of silicon single crystal, characterized in that an etch-stop layer is provided at the site where etching is to be stopped, and that an etch-stop layer having insulating property is provided as the insulating layer of the pressure-sensitive portion.