Abstract: An oscillator is provided, in particular a surface acoustic wave oscillator, frequency controlled by controlling its temperature, which oscillator comprises a SAW resonator frequency controlled by an integral loop including a heating means coupled thermally to the resonator and by two electric respectively proportional and semi-integral loops.

Abstract: A frequency synthesizer for adding large frequency steps to an initial frequency. A first phase lock loop divides the input frequency Fo+.DELTA.(.DELTA. being the sum of smaller frequency steps) by a rational division factor and adds to the result a standard frequency P in a fixed integral ratio with the large frequency steps to form an intermediate frequency Fi. A second phase lock loop (O.sub.S -E-G-D.sub.3 -CPF.sub.2 -FL.sub.3) multiplies the intermediate frequency by a rational factor, equal to (N+1)/D. This second loop first divides (in D.sub.3) the intermediate frequency by an integral fixed ratio D and then compares (in CPF.sub.2) the result Fi/D to a beat between the output frequency Fs and a harmonic N-Fi of the intermediate frequency.

Abstract: A doubly balanced mixer comprising a ring modulator each leg of which is formed by the series connection of a high speed switching diode and one or more diodes with low intrinsic resistance and with high accumulated charges, preferably of the "varactor" or "PIN" type.

Abstract: A decimal frequency synthesizer in which, for each decade, two identical sets of four arithmetic progression frequencies are generated by programmed frequency divisions effected in parallel from a standard frequency and applied to two mixers. The first mixer further receives the frequency from the preceding decade and is followed by a divide-by-2 divider, whereas the second mixer is further receives the output of said divider and is followed by a divide-by-5 divider.

Abstract: A microwave coaxial switch has a central conductor which comprises two fixed segments connected by a movable segment, controlled by a switch member. The resilient ends of the fixed segments come into engagement with the contacts of a quadripole such as an attenuator cell, when they are freed from the movable segment, this latter having come into engagement with the ground conductor.

Abstract: A crystal oscillator comprises an active coupling member driving the series mode resonance of a piezoelectric crystal proportionally to a feedback voltage. Said coupling member is followed by a current boosting transformer whose secondary winding is connected to an output amplifier and to a clipping amplifier shunted across said secondary winding and itself followed by a band-pass filter which supplies said feedback voltage to said coupling member.

Abstract: A binary frequency divider comprises a plurality of serially connected trigger circuits each comprising a switching means having first, second and third terminals and control means for connecting the first terminal alternately to the second terminal and to the third terminal; first storage means connecting the first terminal to the earth; second storage means connecting the third terminal to the earth, and an amplifier having a negative gain whose absolute value exceeds unity, said amplifier having an input connected to the third terminal and an output connected to the second terminal. This frequency divider is particularly adapted for use in the micro-wave and very high frequency ranges.