Facsimile Signal Discrimination via Multi-Bank Filtering
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Solution Overview
Problem
Existing facsimile communication systems risk erroneously transmitting data to incorrect terminals due to voice signals being misinterpreted as dial tone signals, leading to potential leakage of confidential information.
Innovation Solution
A facsimile apparatus with a communication unit, line seizing unit, and determining unit that discriminates between dial tone and voice signals, controlling facsimile communication to prevent erroneous transmissions by using multiple filters to detect signal frequencies and patterns, and ensuring accurate line connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the facsimile terminal detects signals based on frequency and pattern matching during line seizure, then dial tone detection capability is improved, but the risk of erroneously identifying voice signals as dial tone signals increases
Solution Approach 1:
The patent divides the signal detection process into multiple independent filter banks, each targeting specific frequency ranges. Instead of using a single detection mechanism, the system segments the frequency spectrum into multiple bands (e.g., 300-700 Hz, 700-1100 Hz, etc.) and applies separate detection logic to each segment, thereby improving both detection accuracy and reliability through distributed analysis
Solution Approach 2:
The patent introduces an intermediary verification mechanism that acts as a mediator between signal detection and facsimile communication initiation. The determining unit serves as an intermediary layer that cross-checks detected signals against multiple criteria (frequency matching, pattern consistency, source verification) before confirming dial tone status, preventing erroneous identification of voice signals
2Speed
If the system uses stored frequency and pattern data for dial tone detection, then detection speed is improved, but the ability to distinguish between dial tone and voice signals deteriorates
Solution Approach 1:
The patent implements dynamic detection criteria that adapt based on the detection context. The system continuously monitors signal characteristics and adjusts detection thresholds and filter parameters in real-time, allowing it to maintain high detection speed while dynamically improving discrimination accuracy between dial tone and voice signals based on observed patterns
Solution Approach 2:
The patent adds additional detection dimensions beyond simple frequency matching. It incorporates temporal pattern analysis, signal source identification, and multi-filter correlation as additional dimensions for signal verification. This multi-dimensional approach enables the system to maintain fast detection while achieving superior signal type discrimination through cross-validation across multiple parameters
3Productivity
If line seizing operation conflicts with incoming call reception, then the facsimile transmission process is disrupted, but the system lacks the capability to identify and prevent erroneous connections
Solution Approach 1:
The patent performs preliminary verification of detected signals before initiating facsimile communication. The determining unit conducts pre-checks to verify that the detected dial tone signal is genuine and not a coincidental voice signal from an incoming call. This preliminary action prevents erroneous connections before they occur, maintaining both productivity and reliability
Data Source
AI summary
When facsimile data is transmitted by performing facsimile communication, a public line is seized. Then, when the public line is seized, it is a determined which of a dial tone signal or a voice signal for phone call a signal received from the public line is, it is controlled to perform the facsimile communication in a case where the received signal is determined as the dial tone signal, and it is controlled not to perform the facsimile communication in a case where the received signal is determined as the voice signal.