Abstract: In a receiver circuit, an analog signal processor frequency-converts an input high frequency signal into a baseband signal, and performs low pass filtering at a cutoff frequency below a desired-wave band. An ADC converts an output of the analog signal processor into a digital signal. A digital signal processor compensates an output of the ADC for a signal component in the desired-wave band which has been attenuated by the filtering operation of the analog signal processor.

Abstract: A presented semiconductor integrated circuit, which processes an RF signal, achieves preferable distortion characteristics even at the low supply voltage. It includes an attenuator configured to attenuate an input signal with a variable attenuation, a source follower configured to receive an output of the attenuator, and an amplifying unit configured to perform a filtering process on an output of the source follower, and then amplify the output of the source follower with a variable gain.

Abstract: In a receiver circuit, an analog signal processor frequency-converts an input high frequency signal into a baseband signal, and performs low pass filtering at a cutoff frequency below a desired-wave band. An ADC converts an output of the analog signal processor into a digital signal. A digital signal processor compensates an output of the ADC for a signal component in the desired-wave band which has been attenuated by the filtering operation of the analog signal processor.

Abstract: A cascode amplification unit includes a plurality of cascode amplifiers connected in parallel. Each of the cascode amplifiers has two transistors. A cascode current source unit includes a plurality of cascode current sources connected in parallel. Each of the cascode current sources has two transistors. Both the output end of the cascode amplification unit and the output end of the cascode current source unit are connected to a load circuit. The control circuit turns on and off each cascode transistor of the cascode amplifier and each cascode transistor of the cascode current source so that an amount of current passing through the load circuit is constant.

Abstract: A cascode amplification unit includes a plurality of cascode amplifiers connected in parallel. Each of the cascode amplifiers has two transistors. A cascode current source unit includes a plurality of cascode current sources connected in parallel. Each of the cascode current sources has two transistors. Both the output end of the cascode amplification unit and the output end of the cascode current source unit are connected to a load circuit. The control circuit turns on and off each cascode transistor of the cascode amplifier and each cascode transistor of the cascode current source so that an amount of current passing through the load circuit is constant.

Abstract: In an interpolative modulator, a signal which varies by only .+-.1 with one clock from a 1-bit quantizer is used as a shift-direction control signal. The shift-direction control signal is given to a bidirectional shift register. The bidirectional shift register shifts data based on the value of the shift-direction control signal that has been received. The output from the bidirectional shift register is given as a control signal to a resistive-ladder-type D/A converter. The resistive-ladder-type D/A converter outputs an analog potential corresponding to a switch selected by the above control signal. Therefore, if a delay difference occurs between any two bits, two adjacent switches are simply selected simultaneously, so that the output from the resistive-ladder-type D/A converter varies continuously. Consequently, there can be provided an oversampling D/A converter of resistive-ladder type with high accuracy and an increased yield, which is free from glitch (transiently generated noise).

Abstract: An illuminator for a microscope contains a source of light and the microscope has a stage with an opening for upward passage of light from the light source to illuminate a specimen on the stage. The housing defines a window for passage of light from the source through the opening in the stage for illuminating the specimen. The housing also includes first and second support arms, and the housing is adjustable both horizontally and vertically, e.g. relative to the opening in the microscope stage.

Abstract: A microscope has a microscope stand with a specimen stage for viewing and a microscope tube mounted on the stand, the tube having an eyepiece at one end and an objective at the other end, adjacent the stage. The tube is constructed for axial adjustment to vary the position of the objective relative to a specimen on the stage, both by application of axially directed force for coarse focus adjustment and by application of rotational force for fine focus adjustment.

Abstract: A illuminator base for illumination of a microscope specimen from below the specimen includes a fluorescent lamp bulb for generation of illuminating light on a viewing axis. The fluorescent lamp bulb has at least two arms, each having an active volume within a glass wall. The arms are disposed with each active volume generally tangent to the viewing axis. A line intersecting the viewing axis and the axes of lamp arms lies at an acute angle to the viewing axis. Preferably the lamp bulb is u-shape, the angle is about 40.degree. and 50.degree., and light transmitted by the lamp arms along the viewing axis is substantially without shadow.