Abstract: A system and method for simulating the noise characteristics of phase locked loops (PLL's) and other devices. Voltage Controlled Oscillator (VCO) transfer function and phase noise data is first imported for a particular circuit from a Radio Frequency (RF) simulator. The phase locked loop blocks in the circuit are converted to calibrated behavioral-level models. A combined analog/digital model is used to model the VCO, which in turn uses a pseudorandom signal generator for simulating VCO noise. Information about VCO periods is then written to a file or memory for post-processing, such as creating noise spectrum data and noise spectrum plots.

Abstract: A method and apparatus for providing a lower frequency signal with reference to a higher frequency signal are disclosed. The apparatus of the invention comprises an oscillating signal generator, an integer logical divider, and a signal combiner. The signal generator receives an input voltage and, in response thereto, generates a first output oscillating signal and a second output oscillating signal, both having a first frequency. The two oscillating signals are separated by a ninety-degree phase shift. The integer logical divider receives the two oscillating signals and provides two output divided signals in response. The first divided signal is representative of the first oscillating signal except that its frequency is one-third the frequency of the first oscillating signal. Likewise, the second divided signal is representative of the second oscillating signal except that its frequency is one-third that of the second oscillating signal.

Abstract: A converter (300) for converting an a.c. voltage (SP) into a direct current (i.sub.3), characterized in that it comprises a first elementary converter (21) which, in response to the a.c. voltage (SP), provides a pulsed direct current (i.sub.1), the mean value (i.sub.1) of which is a steeply rising function of the amplitude A of the a.c. voltage (SP), and a second elementary converter (22) which, in response to the current i.sub.1 provides a current i.sub.3, the value of which is a steeply falling function of i.sub.1.Used for regulating the amplitude of the oscillation signal of an oscillator.

Abstract: A voltage level detector circuit, which enables an input voltage to be compared with a predetermined stable reference level, defined on the basis of the sum of a first value of the direct voltage across the terminals of a diode and of the product of the difference between this first value and a second value of the voltage across the terminals of the diode by a predetermined coefficient, comprises substantially identical bipolar transistors (1, 2), connected as diodes, in series with current sources (3, 4) for generating voltages representative of these first and second values, a capacitive calculating circuit (5-8) which produces a signal representative of the algebraic value of the difference between the input voltage and the reference level and an amplifier (9) for bringing this signal to a logic level.

Abstract: An amplifier includes an inverter with two transistors of complementary types. The first transistor is biased through a third transistor of the same type of conductivity by a first reference voltage, the third transistor being biased by a third voltage of reference. The second transistor is biased through a fourth transistor of the same type of conductivity by a second voltage of reference, the fourth transistor being biased by a fourth voltage of reference. The first and second voltages of reference are determined so that without any alternating input signal the current in the first and second transistors of the inverter is minimum. The third and fourth voltages of reference are determined so that the equivalent resistances of the third and fourth transistors are very high.

Abstract: The converter comprises a first MOS transistor fed by a current source or by a current-limiting element and it receives through an input capacitor the alternating input voltage. The first transistor is biased by a second MOS transistor the distance drain-source of which is connected between the gate and the drain of the first transistor. The second transistor is biased on its gate by a voltage of reference in such a way that its equivalent internal resistance takes a very high value. A filter capacitor is connected between drain and source of the first transistor. A direct voltage is delivered on the drain of the first transistor the value of which being function of the amplitude of the alternating input voltage. The converter can be implemented by any conventional technology for MOS integrated circuits because it uses only standards elements which are easily integrated.