Itt Manufacturing Enterprises, Inc.

Nortel Networks Corporation

Florin Pera

Stepan Iliasevitch

Dennis R Whittaker

Marinette Besson

A differential amplifier includes a first electrical path formed between a first transistor and a first load impedance; a second electrical path formed between a second transistor and a second load impedance; a tail-current transistor coupled to the first and second transistors; an input end of a feedback amplifier coupled directly to the first and second electrical paths for receiving a differential voltage output signal; and an output end of the feedback amplifier coupled directly to the tail-current transistor for adjusting the current provided through each of the first and second electrical paths. The feedback amplifier includes a non-inverting input node and an inverting input node, each node coupled directly to one or the other of the first and second electrical paths.

Differential amplifier with current source controlled through differential feedback

A comparator includes a differential pair of transistors providing a first amplification stage and receiving inverting and non-inverting input signals. An output transistor is coupled to the differential pair of transistors providing a second amplification stage and transitioning the output signal state when the non-inverting input signal is larger than the inverting input signal. The output node of one of the differential pair of transistors is connected to an input node of a current-tail transistor. The output node of the other differential transistor is connected to an input node of the output transistor. The other nodes of the differential pair of transistors are connected to each other and are coupled to an output node of the current-tail transistor. The output nodes of the differential pair of transistors and an output node of the output transistor are each coupled to a separate current generator that may include a complex impedance element.

High gain, high speed comparator operable at low current

A phase lock loop (PLL) includes a voltage controlled oscillator (VCO) for providing a VCO output signal. A first phase/frequency detector (PFD) for providing a first voltage tuning signal is included for controlling a frequency of the VCO output signal by comparing a first reference signal to the VCO output signal. A second phase/frequency detector (PFD) for providing a second voltage tuning signal is included for controlling the frequency of the VCO output signal by comparing a second reference signal to the VCO output signal. The first and second voltage tuning signals provide, respectively, first and second gains of frequency per volt for controlling the frequency of the VCO output signal. The first voltage tuning signal has a higher gain than the second voltage tuning signal. The first voltage tuning signal provides coarse frequency control of the VCO output signal and the second voltage tuning signal provides fine frequency control of the VCO output signal.

Low noise phase locked loop with a high precision lock detector

A signal-level compensating system consists of a voltage-follower stage, a sensor and a output signal compensator. The voltage-follower stage includes a signal input for receiving an input signal, a signal output, and at least one transistor coupled between the signal input and the signal output for providing an output signal responsive to the input signal. The sensor provides a control signal indicative of variations in at least one of the power supply voltage and transistor characteristics of the transistor. The output signal compensator is coupled to the signal output and provides a compensator output signal responsive to the control signal for reducing the impact of the variations on the voltage-follower output signal.

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Kanata, Canada

Florin Pera