Abstract: A mixer circuit with a conventional very high frequency circuit for the reception of color television bands I and III, which is connected dependent on the band and which is provided with an NPN transistor. The NPN transistor operates via a collector resistor onto a two circuit band filter. Moire interferences in the band I region expanded for CATV are avoided by having the mixer current used to 0.3 to 0.6 mA via a counter coupling resistor disposed between base and hot end of the resistor 4. Thus the self-interference in band I is reduced by a value of about 60 dB. In case of band III operation the corresponding switching voltage is fed via a series connection of a diode 6 and a resistor 5 to the base and thus the base level is lifted up to higher mixing current, since in band III self-interferences cannot occur in the case of the presence of signals.

Abstract: A gas laser havinng a cylindrically-shaped discharge tube in which at least one end is terminated with a metal end cap which supports a mirror body in its central area, supports a metal pump stem in a position eccentric to the longitudinal axis of the tube and supports a thermal compensation element in a position opposite and radially symmetrical to the pump stem whereby at gas laser operating temperatures, the compensation element deforms the metal end cap to substantially the same extent as the pump stem so that the influence of cap deformation on the mirror orientation relative to the longitudinal axis of the tube is minimized or at least approximately compensated.