Tracking Bandpass Receiver With Harmonic-Suppressing Lowpass Filter
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Solution Overview
Problem
Existing radio frequency (RF) receivers, particularly television receivers, face challenges in achieving high quality at low cost due to the need for discrete components like inductors and varactors, which are expensive and difficult to integrate with silicon-based technologies, leading to increased costs and size.
Innovation Solution
A receiver architecture incorporating a tracking bandpass filter with an integrated passive device (IPD) die and a tunable lowpass filter, combined with a local oscillator and mixer, uses a square wave local oscillator signal to mix the RF signal to a desired intermediate frequency, while the tunable lowpass filter attenuates the third harmonic, enabling efficient channel tuning and filtering without the need for expensive silicon manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete components (inductors, varactors, capacitors) are used to build high-quality television receivers, then receiver performance is improved, but cost and device complexity increase
Solution Approach 1:
The patent combines multiple discrete components (inductors, capacitors, varactors) into an integrated passive device (IPD) that provides tracking bandpass filtering functionality. This merging reduces the number of separate discrete components needed while maintaining the high-selectivity filtering performance required for television receiver operation across wide frequency ranges.
Solution Approach 2:
The IPD is designed to provide multi-functional capability, serving as a tracking bandpass filter that can operate across multiple television channels and frequency ranges. The device integrates inductors, capacitors, and varactors to simultaneously provide resonance, filtering, and tuning functions that would otherwise require separate discrete components.
2Manufacturing precision
If discrete components are used to achieve high-quality filtering, then filtering performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple discrete passive components into a single IPD that can be manufactured using integrated circuit fabrication processes. This combination enables high-quality filtering performance to be achieved through standardized manufacturing techniques rather than assembly of expensive discrete components, reducing overall manufacturing cost.
Solution Approach 2:
The IPD incorporates varactor diodes that allow electronic tuning of resonant frequencies and filtering characteristics. By changing the electrical parameters (capacitance values) through voltage control rather than physical component changes, the system achieves high-performance filtering across multiple channels while simplifying manufacturing and enabling programmable frequency selection.
3Ease of manufacture
If silicon-based integrated circuit technology is used to reduce cost, then manufacturing cost decreases, but filtering performance deteriorates
Solution Approach 1:
The patent employs a composite structure within the IPD, combining silicon-based integrated circuit technology with carefully designed passive components (inductors, capacitors, varactors) that are optimized for RF performance. This composite approach allows the benefits of low-cost silicon manufacturing while incorporating specialized components that maintain high-quality filtering performance required for television reception.
Solution Approach 2:
The IPD uses varactor diodes to enable electronic control of resonant frequencies and filtering parameters. By changing electrical parameters through voltage control rather than requiring precise physical manufacturing tolerances, the system achieves high-performance filtering using standard silicon fabrication processes, bridging the gap between low-cost manufacturing and high performance.
4Reliability
If external discrete components are added to integrated circuit receivers to maintain performance, then receiver performance is maintained, but cost increases
Solution Approach 1:
The patent merges the tracking bandpass filter functionality that would traditionally require external discrete components directly into an integrated IPD. This integration eliminates the need for separate external components while maintaining the high-selectivity filtering performance necessary for proper receiver operation, thereby reducing both cost and device complexity.
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 approach allows for high-quality RF filtering at a lower cost by integrating inductors on an IPD die and using a dual-filter architecture, reducing the complexity and cost of the receiver while maintaining performance, and enabling compact size.
Implementation Method 1
a tracking bandpass filter (420) having an input for receiving a radio frequency (RF) input signal and an output
Implementation Method 2
The tunable lowpass filter is configured to substantially attenuate a third harmonic of a frequency of the local oscillator signal
Implementation Method 3
a mixer having a first input coupled to the output of the tunable lowpass filter, a second input coupled to the first output of the local oscillator, and a first output for providing an IF signal
Data Source
AI summary
A receiver (400) includes a tracking bandpass filter (420), a tunable lowpass filter (434), a local oscillator (442), and a mixer (444). The tracking bandpass filter (420) has an input for receiving a radio frequency (RF) input signal, and an output. The tunable lowpass filter (434) has an input coupled to the output of the tracking bandpass filter (420), and an output. The local oscillator (422) has a first output for providing a local oscillator signal, which is characterized as being a square wave signal at the desired intermediate frequency (IF). The mixer (444) has a first input coupled to the output of the tunable lowpass filter (434), a second input coupled to the output of the local oscillator (442), and a first output for providing an IF signal at the desired IF. The tunable lowpass filter (434) is configured to substantially attenuate a third harmonic of the frequency of the local oscillator signal.