This series of articles discusses oscillator phase noise reduction techniques and gives specific resonant circuit solutions using lumped and distributed parameters for both frequency stabilization and phase noise reduction. These topics are covered in Part 1. Phase noise improvement can also be achieved by appropriate low-frequency loading and feedback circuitry optimization. The feedback syste...

Modulatory projection neurons gate neuronal networks, such as those comprising motor central pattern generators; in turn, they receive feedback from the networks they gate. A recent study has shown that, in the crab stomatogastric ganglion, this feedback is also subject to modulation: the enhanced feedback feeds forward through the projection neurons to modify circuit output.

Two-circuit models for feedback subcircuits are developed from a modification to the two-port method of feedback amplifier analysis and are applied in a method to break the feedback loop. These models are terminally equivalent to linear and nonlinear subcircuits, have physically-disconnected topologies, and employ dependent sources to control lateral signal transfer with a switch-like on or off...

Cortical feedback pathways are hypothesized to distribute context-dependent signals during flexible behavior. Recent experimental work has attempted to understand the mechanisms by which cortical feedback inputs modulate their target regions. Within the mouse whisker sensorimotor system, cortical feedback stimulation modulates spontaneous activity and sensory responsiveness, leading to enhanced...

Four circuit schemes that use partial positive feedback for gain enhancement in CMOS OTAs are examined. These circuit schemes are classiied as type I and type II circuits. Type I circuits use a diierential input pair with positive feedback and type II circuits use a active load with positive feedback. As the primary emphasis of these circuits is for micropower operation, the circuits have been ...

Synaptic feedback from rhythmically active neuronal circuits commonly causes their descending inputs to exhibit the rhythmic activity pattern generated by that circuit. In most cases, however, the function of this rhythmic feedback is unknown. In fact, generally these inputs can still activate the target circuit when driven in a tonic activity pattern. We are using the crab stomatogastric nervo...

An integrate-and-fire-type spiking feedback network is discussed in this paper. In our spiking neuron model, analog information expressing processing results is given by the relative relation of spike firing. Therefore, for spiking feedback networks, all neurons should fire (pseudo-)periodically. However, an integrate-and-fire-type neuron generates no spike unless its internal potential exceeds...

This paper presents an accurate current mode synchronous Loser-Take-All circuit based on a simple regenerative pair. The regenerative pair and the related resetting transistors lead to a circuit requiring only four transistors, seven for deep binary tree structures. It achieves its high speed through regenerative feedback. The basic circuit requires no current mirrors and has only parasitic los...