A technology related to an electronic circuit, specifically, a phase locked loop or a frequency synthesizing apparatus, is disclosed. The frequency synthesizing apparatus includes an injection locked frequency divider and a replica frequency divider having the same circuit configuration as the injection locked frequency divider. A control value required for self-oscillating at a target frequency using the replica frequency divider is determined. When the injection locked frequency divider fails injection locking on a first attempt, the injection locking may be attempted using the determined control value. On the first attempt, the control value of the injection locked frequency divider may be determined and stored in advance according to a temperature and a supply voltage.

A technology related to an electronic circuit, specifically, a phase locked loop or a frequency synthesizing apparatus, is disclosed. The frequency synthesizing apparatus includes an injection locked frequency divider and a replica frequency divider having the same circuit configuration as the injection locked frequency divider. A control value required for self-oscillating at a target frequency using the replica frequency divider is determined. When the injection locked frequency divider fails injection locking on a first attempt, the injection locking may be attempted using the determined control value. On the first attempt, the control value of the injection locked frequency divider may be determined and stored in advance according to a temperature and a supply voltage.

An electronic circuit including: a differential multiplier circuit with a first differential input and a second differential input and a differential output; and a phase locked loop (PLL) circuit including: (1) a balanced differential mixer circuit with a first differential input electrically connected to the differential output of the differential multiplier circuit, a second differential input, and an output; (2) a loop filter having an output and an input electrically connected to the output of the balanced differential mixer circuit; and (3) a voltage controlled oscillator (VCO) circuit having an input electrically connected to the output of the loop filter and with an output electrically feeding back to the second differential input of the balanced differential mixer circuit.

An electronic circuit including: a differential multiplier circuit with a first differential input and a second differential input and a differential output; and a phase locked loop (PLL) circuit including: (1) a balanced differential mixer circuit with a first differential input electrically connected to the differential output of the differential multiplier circuit, a second differential input, and an output; (2) a loop filter having an output and an input electrically connected to the output of the balanced differential mixer circuit; and (3) a voltage controlled oscillator (VCO) circuit having an input electrically connected to the output of the loop filter and with an output electrically feeding back to the second differential input of the balanced differential mixer circuit.

A method of frequency doubling includes receiving a first clock that has a fifty percent duty cycle and is a two-phase clock having a first phase and a second phase; outputting a second clock using a multiplexer by selecting one of the first phase and the second phase of the first clock in accordance with a third clock; delaying the second clock into a fourth clock using a recirculating delay circuit; and using a divide-by-two circuit to output the third clock in accordance with the fourth clock.

A method of frequency doubling includes receiving a first clock that has a fifty percent duty cycle and is a two-phase clock having a first phase and a second phase; outputting a second clock using a multiplexer by selecting one of the first phase and the second phase of the first clock in accordance with a third clock; delaying the second clock into a fourth clock using a recirculating delay circuit; and using a divide-by-two circuit to output the third clock in accordance with the fourth clock.

An oscillator circuit includes a core stage having a voltage controlled oscillator arranged to output an output oscillation signal, and an input stage coupled to the output stage via an induction coupling, and arranged to receive an input oscillation signal; wherein the output oscillation signal includes an output oscillation frequency substantially equals to a multiplication of an input oscillation frequency of the input oscillation signal.

A circuit includes an input port receiving an input signal having a first frequency. A phase-shifter network is coupled to the input port, receives the input signal, and produces therefrom first and second signals in quadrature with one another. Frequency multiplier circuitry has a common node and includes a first rectifier for rectifying the first signal to produce a first rectified signal having a second frequency that is twice the first frequency and to be applied to the common node, and a second rectifier rectifying the second signal to produce a second rectified signal having the second frequency and to be applied to the common node. A combination of the first and second rectified signals is available at the common node and includes harmonic contents at a frequency that is fourfold the first frequency.

In an embodiment, a circuit for tripling frequency is configured to receive an input voltage (V.sub.in) having a sinusoidal shape and a base frequency. The circuit has a first and a second transistor pair that are cross-coupled, and a trans-characteristics f(V.sub.in) approximating a polynomial nominal trans-characteristic given by $f\left(V_{\mathrm{in}}\right)=\left(\frac{3}{A}{V}_{\mathrm{in}}-\frac{4}{A^3}{V}_{\mathrm{in}}^3\right)g_m$
where A represents an amplitude of the input voltage and g.sub.m is a transconductance of transistors of the first and second transistor pairs.

An oscillator circuit includes a core stage having a voltage controlled oscillator arranged to output an output oscillation signal, and an input stage coupled to the output stage via an induction coupling, and arranged to receive an input oscillation signal; wherein the output oscillation signal includes an output oscillation frequency substantially equals to a multiplication of an input oscillation frequency of the input oscillation signal.