Tuner Oscillation Signal Frequency Control for Synthetic Interference
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Solution Overview
Problem
In receiving apparatuses with multiple tuners, the multiplication of oscillation signals can result in a synthetic signal frequency falling within the selected channel's frequency band, leading to deteriorated reception quality.
Innovation Solution
A controller is used to adjust the frequency of the oscillation signals generated by Voltage-Controlled Oscillators (VCOs) in each tuner, ensuring that the synthetic signal frequency does not fall within the selected channel's frequency band by applying a control value that adjusts the oscillation signal to be outside the channel's frequency range, thereby preventing reception quality deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple tuners are used to receive broadcast signals, then the receiving capability is improved, but the reception quality deteriorates due to synthetic signal interference
Solution Approach 1:
The patent changes the frequency parameter of the local oscillator by applying a control value to shift the oscillation frequency away from values that would generate synthetic signals within the selected channel's frequency band. This parameter adjustment prevents the multiplication of oscillation signals from falling within the reception band, thereby resolving the contradiction between multi-tuner capability and reception quality.
2Reliability
If the local oscillator frequency is adjusted to avoid synthetic signal interference, then the reception quality is improved, but the frequency selection complexity increases
Solution Approach 1:
The patent applies a control value to the local oscillator frequency in advance to prevent synthetic signal generation. By pre-adjusting the frequency before the interference problem occurs, the system maintains simple frequency selection while ensuring reception quality, avoiding the need for complex real-time frequency management.
3Reliability
If the oscillation signal frequency is controlled to prevent synthetic signal multiplication, then the signal purity is improved, but the control mechanism complexity increases
Solution Approach 1:
The patent modifies the frequency parameter of the oscillation signal by applying a control value, which directly improves signal purity by preventing synthetic signal multiplication. This parameter change approach maintains a relatively simple control mechanism compared to more complex frequency management systems.
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 effectively prevents reception quality deterioration by ensuring the synthetic signal frequency is outside the selected channel's frequency band, allowing for stable demodulation and improved signal reception.
Implementation Method 1
an oscillation circuit that generates an oscillation signal having a frequency that is constant-fold as high as a frequency in a frequency band of a channel selected by the tuner; and a frequency divider that applies frequency division to the oscillation signal output from the oscillation circuit
Implementation Method 2
a frequency divider that applies frequency division to the oscillation signal output from the oscillation circuit
Implementation Method 3
The broadcast signal (output signal from the antenna) is multiplied by a local oscillation signal output from the local oscillator and undergoes the frequency conversion to turn into a base band signal
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A receiving apparatus comprises: a plurality of tuners; and a controller that controls a frequency of a local oscillation signal from each tuner such that a frequency of a synthetic signal generated by multiplying the local oscillation signals from the plurality of tuners by each other does not fall in a frequency band of a channel selected by each tuner. Deterioration in reception quality due to the multiplication of the local oscillation signals is prevented.