Recursive Delay Line for Phase Noise Measurement

The patent implements a feedback mechanism where the output of the delay line discriminator is fed back through a feedback path with adjustable delay and gain to the input. This feedback loop creates a recursive structure that effectively amplifies the phase noise signal while compensating for the attenuation of low-frequency components, thereby improving measurement sensitivity without requiring complex external equipment

The patent transitions from a single-delay-path architecture to a multi-dimensional recursive structure by adding feedback paths with different delay values and gains. This creates a system that operates in multiple delay dimensions simultaneously, allowing the combination of multiple delayed versions of the signal to enhance sensitivity while maintaining system simplicity

The patent divides the required long delay function into multiple shorter delay segments. Instead of implementing a single long delay line which is difficult to manufacture, the system uses multiple shorter delay lines with delay values τ1, τ2, ..., τn, each of which is easy to implement. These segmented delays are combined through the feedback mechanism to achieve the equivalent effect of a long delay while maintaining manufacturing simplicity

The patent employs a nested structure where multiple delay paths are embedded within a feedback loop. The feedback path contains additional delay elements nested within the main signal path, creating a hierarchical delay structure. This nesting allows the system to achieve long effective delay through iterative processing rather than requiring a single long physical delay line