Optical Receiver Resistor Ratio Adjustment for Pulse Width Fidelity
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Solution Overview
Problem
Optical interconnection circuits face challenges in maintaining pulse width integrity due to amplitude voltage regulation in differential amplifiers, leading to transmission errors and distorted waveforms.
Innovation Solution
An optical receiving circuit with an adjustment circuit that adjusts the resistance ratio in the resistor network to maintain the waveform integrity of output signals, even when amplitude voltage regulation occurs, by altering the voltage division ratio of resistors R1 and R2, ensuring the output voltage waveform matches the optical input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamping circuit is added to regulate the amplitude voltage of the differential amplifier, then the amplitude voltage is regulated within a predetermined range, but the pulse widths of the output voltages are widened causing distortion
Solution Approach 1:
The patent applies the Dynamics principle by making the resistance ratio in the resistor network adjustable rather than fixed. The adjustment circuit dynamically changes the resistance ratio based on the input signal characteristics, allowing the system to adapt between different operating conditions (with or without clamping) and eliminate pulse width distortion while maintaining amplitude regulation
Solution Approach 2:
The patent implements Parameter changes by varying the resistance ratio parameter in the resistor network. When the input signal requires clamping, the adjustment circuit modifies the resistance ratio to compensate for the pulse width widening effect, thereby maintaining accurate pulse width representation in the output signal
2Device complexity
If the resistance ratio in the resistor network is fixed to generate crossed oscillations, then the circuit configuration is simple, but the output waveform cannot match the optical input when amplitude regulation occurs
Solution Approach 1:
The patent transforms the static resistor network into a dynamic one by adding the adjustment circuit that can modify the resistance ratio. This dynamic capability allows the system to maintain waveform accuracy under varying operating conditions without substantially increasing circuit complexity
Solution Approach 2:
The adjustment circuit automatically detects when amplitude regulation is occurring and self-adjusts the resistance ratio accordingly, eliminating the need for external manual calibration or complex control systems while maintaining waveform fidelity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces pulse width distortion and maintains high data transmission efficiency with undistorted waveforms, suitable for handling a wide range of input signals, including burst signals, while minimizing power consumption and circuit complexity.
Implementation Method 1
an optical semiconductor detector (hereinafter, referred to as PD (photodiode)) 1 that converts an optical input L into a current signal
Data Source
AI summary
Provided is an optical receiving circuit that reduces a distortion of an output pulse width with respect to an input signal by adjusting the division ratio for a voltage applied to resistors in a resistor network. The optical receiving circuit includes: a differential amplifier 2 that converts a current signal converted from an optical input L and outputs a non-inverting voltage V+ and an inverting voltage V− whose amplitudes are regulated; a peak detector 5 that detects a peak voltage Vp of the non-inverting voltage V+ and outputs the peak voltage Vp; a resistor network 4 performing a summation operation based on the peak voltage Vp, the non-inverting voltage V+, and the inverting voltage V− to thereby generate a non-inverting input voltage V1+ and an inverting input voltage V1− whose oscillations cross each other at the middle points of the amplitudes thereof; a discriminator 3 that discriminates a potential at which the oscillations of the non-inverting input voltage V1+ and the inverting input voltage V1− cross each other, and generates a rectangular signal in accordance with the cross potential; and an adjustment circuit 6 that, when the non-inverting voltage V+ or the inverting voltage V− is outputted with the amplitude thereof regulated in the differential circuit, adjusts a relative ratio between the voltages connected respectively to resistors of the resistor network 4, in such a way that the rectangular signal is outputted in the same waveform as the optical input L.