Abstract: Passive frequency measuring circuit comprising a number of frequency discriminators to obtain a digital code representing the frequency of an applied r.f. signal. Each discriminator is tuned to different frequency ranges, and provided with a plurality of similar frequency analysers for the phase detection of the applied r.f. signal passed through different delay lines. As each discriminator delivers an ambiguous code at the boundaries of its characteristic, a digital filter is incorporated to resolve the ambiguity. If such an ambiguity is established, an adjoining discriminator is activated to deliver information for obtaining a digital code representing an unambiguous frequency value.

Abstract: A mixer is provided with a first waveguide part for the transmission of an input signal to be converted to a lower frequency band and with a second waveguide part for the transmission of a signal supplied by a local oscillator. The first and second waveguide parts open into a cavity containing a semiconductor which, disposed of its encapsulation, is mounted on a substrate and is used to obtain an output signal. The frequencies (f.sub.u) of the output signal form a linear combination of the frequencies (f.sub.s) of the input signal and the local oscillator frequency (f.sub.LO). The substrate comprises at least two microwave integrated circuits, forming a connection between the semiconductor and the two waveguide parts, while the mixer further comprises a transmission line for the output signal.

Abstract: With a method for the fabrication of multilayers a laminate is obtained by the stacking of layers, which are formed by a carrier provided with a conductor pattern and interleaved by adhesive layers. The laminate is subjected to a process which is carried out in at least three phases: in the first phase moisture and air are extracted from the space in which the laminate is placed, in the second phase the laminate is pressed together under increasing temperature and in the third phase the pressing process is performed under another temperature rise to a certain maximum value and under a further increase in pressure, while air is admitted into the space where the laminate is situated.