A high performance oscillator with low frequency pulling at turn on includes an oscillator transistor, a resonating element and a common base buffer transistor. The resonating element of the oscillator is a circuit having a crystal resonator that is connected in parallel with a transformer winding. This resonating element is connected between the emitter of the oscillator transistor and the emitter of the buffer transistor. More specifically, a tap connects the emitter of the buffer transistor to the transformer winding of the resonating element. With this connection, a low transformed power oscillating output is taken from the collector of the buffer transistor with minimized degradation in the symbol of merit for the crystal oscillator.
The invention discloses an apparatus and method for reducing frequency pulling. Further, the invention provides amplitude modulation techniques to eliminate spurious signals and injection locking of the VCO to the output transmitted carrier. The architecture includes at least one synthesizer, a plurality of frequency dividers, an output VCO, a low pass filter, a mixer, a pretransmission filter and an amplifier connected in a manner to generate an output frequency which is non-harmonically related to the synthesizer VCO and to maintain the magnitude of the output frequency at, preferably, exactly 1.5 times higher than the VCO frequency.
The oscillator of the present invention generally comprises a resonating device that is directly coupled to ground and a circuit portion. The circuit portion is operably coupled to the resonating device and includes a first transistor and a second transistor. The first transistor provides DC feedback to the second transistor and enables a temperature independent bias current through said second transistor.
