Abstract: A placement apparatus for placing a workpiece is provided. The placement apparatus includes a stage on which a workpiece can be placed in a processing vessel; an edge ring including a locking part which is disposed on the stage so as to surround a periphery of the workpiece; a conductive connecting member connected with the edge ring at the locking part; and a first contacting member configured to cause the edge ring to contact the stage, while the edge ring is connected with the connecting member.

Abstract: Automatic gain control of a communications receiver is provided by including a filter in the upper end thereof having a frequency pass-band which slopes off at each end and can be controllably shifted in a direction and by an amount determined by a control voltage which corresponds to the output signal level. As a result of such shifting of the frequency band relative to the frequency of a received signal, the filter provides adequate gain reduction even for unduly strong received signals and with less signal distortion and lower power consumption than occurs with AGC circuits which operate by changing the bias of a gain control amplifier. If the receiver employs a PLL with a voltage-controlled oscillator, the VCO control signal can be combined with the gain control voltage so as to control the center frequency of the filter pass-band as well as the amount by which it is shifted in order to provide gain control.