Abstract:
The invention concerns a method for stabilizing the operation of a voltage-controlled oscillator (VCO) monitored by a phase locked loop (PLL), the voltage-controlled oscillator delivering a RF signal and receiving via at least one disturbance path a frequency harmonics component equal or close to that of the RF signal, capable of disturbing its operation by injection pulling effect. The invention is characterized in that the method comprises a step which consists in injecting into the voltage-controlled oscillator a signal for compensating the injection pulling effect, whereof the phase and amplitude are adjusted to as to neutralize the effects of the disturbance harmonics component. The invention is applicable in particular to IQ phase modulation in radiotelephony.
Abstract:
L'invention concerne un procédé pour stabiliser le fonctionnement d'un oscillateur contrôlé en tension (VCO) piloté par une boucle à verrouillage de phase (PLL), l'oscillateur contrôlé en tension délivrant un signal RF et recevant par l'intermédiaire d'au moins un chemin parasite une composante harmonique de fréquence égale ou proche de celle du signal RF, susceptible de perturber son fonctionnement par effet d'accrochage en fréquence. Selon l'invention, le procédé comprend une étape d'injection dans l'oscillateur contrôlé en tension d'un signal de compensation de l'effet d'accrochage en fréquence, dont la phase et l'amplitude sont ajustées de manière à neutraliser les effets de la composante harmonique parasite. Application notamment aux circuits de modulation de phase IQ en radiotéléphonie.
Abstract:
Technique for reducing local oscillator leakage in integrated frequency conversion circuits. The technique includes the step of coupling an external portion (35) of a resonator circuit (31, 35) to the integrated frequency conversion circuit (200). The coupling is accomplished without using any of the DC power or ground pins of the conversion circuit. A frequency conversion circuit based on this technique includes resonator, oscillator, and mixer circuits. Part of the oscillator and mixer circuit (16, 13) is encapsulated in a package (200), whereas at least a portion of the resonator circuit (35) is located outside the package. The outside portion of the resonator circuit (35) connects to at least two external resonator pins (43a, 43b) of the package (200) such that, during the operating of the conversion circuit, the net current entering the package via said external resonator pins (43a, 43b) is approximately zero.