Variable Noise Control for Optical Transducer
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Solution Overview
Problem
Infrared (IR) receivers face challenges in rejecting power supply noise, leading to 'dark bits' due to increased susceptibility at high gain conditions, especially as bandwidth increases to accommodate higher data rates, resulting in unwanted signal transitions and reduced performance.
Innovation Solution
An optical transducer with a noise control circuit and switching circuit that adjusts noise control based on changes in optical irradiance, switching the noise control circuit into the power supply path during high gain conditions to enhance power supply rejection ratio (PSRR) and switching it out during low gain conditions to improve responsiveness to high bandwidth transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain of amplifier stages is increased to detect minimal irradiance, then the sensitivity to optical signals is improved, but the susceptibility to power supply noise increases resulting in dark bits
Solution Approach 1:
The patent applies dynamics by making the noise control circuit selectively switchable into and out of the power supply path based on operating conditions. The circuit transitions from a static configuration to a dynamic one where the noise control circuit is engaged only when gain is high and irradiance is minimal, thereby reducing noise susceptibility only when necessary while maintaining detection sensitivity.
Solution Approach 2:
The patent changes the parameter of noise control circuit engagement based on the gain level and irradiance conditions. By monitoring the output signal of the optical transducer and adjusting whether the noise control circuit is active in the power supply path, the system adapts its noise rejection characteristics to match the current operating point, improving PSRR when needed without compromising sensitivity.
2Productivity
If the bandwidth of the receiver is increased to accommodate higher data rates, then the data transmission capability is improved, but the amplification of noise resulting in dark bits becomes more prevalent
Solution Approach 1:
The patent makes the noise control circuit dynamically switchable based on the output signal level from the optical transducer. When data rates are high and bandwidth is increased, the circuit can engage the noise control path to suppress noise amplification. This dynamic adaptation allows the receiver to handle high-speed transmissions while maintaining noise rejection capabilities.
Solution Approach 2:
The patent employs feedback by monitoring the output signal of the optical transducer and using this information to control the switching of the noise control circuit into or out of the power supply path. This closed-loop control ensures that noise suppression is activated when high bandwidth operation makes the system susceptible to noise amplification, thereby maintaining signal integrity at high data rates.
3Reliability
If the noise control circuit is continuously engaged in the power supply path, then the power supply rejection ratio is improved, but the responsiveness to high bandwidth transmissions is reduced
Solution Approach 1:
The patent resolves this contradiction by making the noise control circuit dynamically switchable rather than continuously engaged. The circuit monitors the output signal level and selectively activates noise control only when gain is high and irradiance is minimal. This dynamic engagement maintains high PSRR when needed while allowing the system to respond quickly to high bandwidth transmissions when the noise control circuit is disengaged.
Solution Approach 2:
The patent implements periodic or conditional action by switching the noise control circuit into and out of the power supply path based on varying operating conditions. Rather than continuous engagement, the circuit is activated periodically or conditionally when the output signal indicates minimal irradiance or high gain conditions, thereby balancing noise rejection with transmission responsiveness.
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
The solution effectively reduces the occurrence of 'dark bits' by improving PSRR during high gain conditions and optimizing receiver performance across varying irradiance levels, enabling reliable data transmission over a wide dynamic range.
Implementation Method 1
The transducer generates an output signal representative of optical irradiance
Data Source
AI summary
In one embodiment, an optical transducer, such as an infrared transducer, generates an output signal that is representative of optical irradiance. A noise control circuit is coupled in a power supply path of the optical transducer. A switching circuit varies the noise control provided by the noise control circuit, in response to changes in the output signal of the optical transducer. The noise control may be varied in a number of different ways, including: turning the noise control on or off, varying the noise control in discrete steps, or varying the noise control in a continuous manner. Methods for varying noise control in response to optical irradiance of an optical transducer are also disclosed.