Abstract: A heat exchanger having a pair of manifolds and flat tubes for heat exchange between a first fluidum flowing inside the tubes and a second fluidum flowing outside of the tubes. The manifolds receive ends of the tubes and have an inlet and an outlet for introducing the first fluidum into the flat tubes and for discharging therefrom. Each manifold has at least two adjacent parallel channels with a partition wall therebetween. Each channel is further defined by at least a second wall, with at least part of the second wall having a curved surface. The partition wall defines two parallel substantially flat surfaces facing the channels. Each channel has a perimeter in cross-section defined by a continuous line having curved and straight portions.

Abstract: An RF Amplifier circuit comprises an RF amplifying device having a first input terminal, a second input terminal and an output terminal means for applying to the first input terminal an input FR signal I to be amplified, means for applying to the second input terminal a threshold signal T, and the amplifying device being operable to produce at the output terminal an output signal O which has a high finite value providing a Boolean ‘1’ value when the instantaneous value of the amplitude of I is greater than T and a low finite value providing a Boolean ‘0’ value when the instantaneous value of the amplitude of I is less than T, wherein the threshold signal is dynamically varied in a manner adapted to linearise the relationship in at least part of its range between the amplitude of the output part of its range between the amplitude of the output singal 0 and the amplitude of the input signal I.

Abstract: A heat exchanger comprising a pair of manifolds and a plurality of flat tubes for heat exchange between a first fluidum flowing inside the tubes and a second fluidum flowing outside of the tubes. The manifolds receive ends of the tubes and have an inlet and an outlet for introducing the first fluidum into the flat tubes and for discharging therefrom. Each manifold comprises at least two adjacent parallel channels with a partition wall therebetween. Each channel is further defined by at least a second wall, with at least part of the second wall having a curved surface. The partition wall defines two parallel substantially flat surfaces facing the channels. Each channel has a perimeter in cross-section defined by a continuous line consisting of curved and straight portions.