In-Vehicle FM Tuner Horizontal Sync Adjustment
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Solution Overview
Problem
Broadcast receiving apparatuses with LCD displays face noise interference issues due to harmonic components of the dot clock frequency matching FM broadcast reception frequencies, leading to annoying noises and display quality degradation when switching reception frequencies.
Innovation Solution
A broadcast receiving apparatus that adjusts the horizontal synchronous frequency by varying the horizontal blanking period without changing the number of effective pixels, ensuring the minimum difference between the reception frequency and its multiples is above an audible range, and performs this adjustment during vertical blanking periods to prevent flicker and noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the dot clock frequency is switched to prevent harmonic components from approaching the communication frequency, then noise interference is reduced, but the display quality deteriorates due to flicker and configuration complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the horizontal synchronous frequency based on the reception frequency. Instead of switching between multiple fixed dot clock frequencies, the system continuously tunes the horizontal synchronous frequency to maintain optimal display performance while avoiding harmonic interference with the FM broadcast frequency. This resolves the contradiction by providing a simpler configuration (single dot clock frequency) that adapts to changing conditions.
Solution Approach 2:
The patent implements dynamics by making the horizontal synchronous frequency adjustable rather than fixed. The system dynamically changes the horizontal synchronous frequency in response to changes in reception frequency, allowing the display to adapt to varying broadcast conditions without requiring multiple fixed frequency configurations. This dynamic adjustment prevents harmonic interference while maintaining display quality.
2Object-affected harmful factors
If the dot clock frequency is switched frequently in response to reception frequency changes, then noise interference is reduced, but display quality deteriorates due to flicker
Solution Approach 1:
The patent applies feedback by monitoring the reception frequency and using this information to adjust the horizontal synchronous frequency accordingly. The system establishes a feedback loop where changes in reception frequency trigger corresponding adjustments in the horizontal synchronous frequency, ensuring that harmonic components remain away from the reception frequency while maintaining stable display performance without flicker.
Solution Approach 2:
The patent uses parameter changes to resolve the contradiction between noise reduction and display quality. By dynamically adjusting the horizontal synchronous frequency parameter in response to reception frequency changes, the system prevents harmonic interference while avoiding the flicker that would result from frequent dot clock frequency switching. The parameter adjustment is made in a way that maintains display stability.
3Adaptability or versatility
If multiple dot clock frequencies are prepared for different resolutions, then adaptability is improved, but device complexity increases significantly
Solution Approach 1:
The patent applies universality by making a single dot clock frequency capable of supporting multiple display resolutions through dynamic adjustment of the horizontal synchronous frequency. Instead of requiring separate dot clock frequencies for different resolutions, the system uses one universal dot clock frequency that can adapt to various resolution requirements by adjusting timing parameters, thereby reducing device complexity while maintaining versatility.
Solution Approach 2:
The patent implements dynamics to achieve adaptability without complexity. The horizontal synchronous frequency is made dynamically adjustable, allowing the same physical display hardware to adapt to different resolution requirements and broadcast conditions. This dynamic capability provides versatility across multiple scenarios without requiring multiple fixed frequency mechanisms or complex reconfiguration systems.
Data Source
AI summary
An in-vehicle apparatus includes an FM radio tuner that receives FM broadcast waves of a reception frequency that is set; a FM radio controller; an LCD unit that is capable of changing a horizontal synchronous frequency corresponding to each horizontal line by varying a horizontal blanking period along the horizontal direction, without changing the numbers of effective pixels in horizontal display and vertical display, and an effective display period; a horizontal synchronous frequency setter that sets the horizontal synchronous frequency so that a minimum value of the differences between the reception frequency of the FM broadcast waves and multiplied frequencies that are integral multiples of the horizontal synchronous frequency is higher than or equal to a certain value; and a video processor that generates a video signal necessary to display at least one of a working screen and an operation screen in the LCD unit.