Infrared Receiver Pulse Shaping Without External Time Base
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Solution Overview
Problem
Existing methods for forming reception pulses in IrDA standard receivers face issues with pulse duration variability, leading to data transfer stalls and high power consumption due to the need for large amplifier bandwidth, and require external time bases or complex circuits for synchronization.
Innovation Solution
A method that delays the input signal from an upstream comparator to create a buffer time for pulse examination, allowing adjustment of output pulse duration based on the input signal level, using a monostable multivibrator switchable in pulse duration, without an external time base, and divides the delay into partial steps for reliable transmission of short pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single monoflop is used for forming single pulses, then the circuit is simple and space-optimum, but the pulse duration becomes excessively long and strongly varying, causing data transfer stalls
Solution Approach 1:
The patent divides the pulse formation process into two independent stages: a first monoflop generates an initial pulse, and a second monoflop generates a follow-up pulse. This segmentation allows each monoflop to be optimized for its specific function, preventing excessive pulse duration while maintaining circuit simplicity. The two-monoflop arrangement reliably produces pulses of appropriate duration without the variability problems of a single monoflop.
2Manufacturing precision
If amplifier bandwidth is increased to satisfy transfer requirements, then single and double pulses can be transferred accurately, but power consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by generating standardized pulses with correct duration and shape at the comparator output stage, before the amplifier. The two-monoflop circuit pre-forms pulses that already meet the required specifications, eliminating the need for the amplifier to perform pulse shaping. This allows the amplifier to operate with reduced bandwidth while maintaining pulse transfer accuracy, thereby reducing power consumption.
3Reliability
If external time base and synchronization circuits are added, then pulse synchronization is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent implements self-service by making the pulse formation circuit self-synchronizing. The two-monoflop arrangement automatically generates pulses with correct timing and duration based on the input signal itself, without requiring external time bases or synchronization circuits. The circuit uses its own output signals to control the timing of subsequent pulses, eliminating the need for additional synchronization hardware and reducing overall system complexity.
Data Source
AI summary
In a method and arrangement for forming reception pulses, output signals of an upstream comparator which recognizes light pulses are used to evaluate a downstream arrangement and are newly formed and emitted as pulses. The aim is to produce a method and an associated circuit arrangement for forming reception pulses which represent a saving in energy, whereby said arrangement can be integrated into existing receiver systems, requires no external time base and can work with the signal of an upstream comparator. In a first step, an input signal delivered by an upstream comparator is delayed, whereupon a time reference is produced in a controlled manner and an output pulse begins to be formed in a controlled manner by means of the delayed input signal from the first step. The input signal level is examined once production of the time reference is completed. The examination refers back to the length of the received pulse, and the duration of the output impulse is adjusted according to the results of the examination.