Integrated Inductor Receiver Tuning Across VHF and UHF Bands
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Solution Overview
Problem
Conventional receiver circuits face challenges in efficiently covering a wide frequency range due to the tradeoff between inductance and quality factor, leading to increased complexity and size of inductive components, which limits the frequency range and increases noise figure.
Innovation Solution
The proposed receiver circuit employs a tracking filter with a low-pass filter for VHFLO, a bandpass filter for VHFHI, and a transformer-based filter for UHF, reducing the number of inductive-capacitive filters and using inductive peaking to extend the frequency range, while maintaining low noise and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of the inductor is increased to increase inductance, then the inductance value is improved, but the quality factor decreases
Solution Approach 1:
The patent divides the frequency range into multiple bands (VHFLO, VHFHI, UHF) and uses different filter configurations for each band. This segmentation allows each filter to be optimized for its specific frequency range, achieving high quality factor without requiring excessively large inductors across the entire frequency spectrum.
Solution Approach 2:
The patent applies different filter topologies and component values tailored to specific frequency bands. For example, VHFLO uses a low-pass filter configuration while UHF uses a bandpass filter, allowing each section to have optimal local characteristics for its frequency range rather than using a uniform design.
2Adaptability or versatility
If multiple bandpass filters are used to cover the frequency range, then the frequency coverage is improved, but the device complexity increases
Solution Approach 1:
The patent designs a tracking filter that can operate across multiple frequency bands (VHFLO, VHFHI, UHF) using a unified filter structure with variable components. This multi-functional approach allows a single filter system to cover the entire frequency range rather than requiring separate dedicated filters for each band.
Solution Approach 2:
The patent employs variable capacitors and switches that can be dynamically reconfigured to change the filter's resonant frequency and bandwidth. This dynamic adjustment capability allows the same physical filter to adapt to different frequency bands without requiring multiple static filter circuits.
3Reliability
If the tuned impedance is increased to minimize noise figure, then the noise figure is improved, but the inductor size increases
Solution Approach 1:
The patent optimizes the inductor quality factor and tuned impedance parameters specifically for each frequency band. By adjusting L and C values to achieve optimal Q-factor at each operating frequency, the design achieves low noise figure without requiring uniformly large inductors across all bands.
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 configuration allows for a reduced number of filters, smaller inductor size, and improved noise figure and linearity, enabling efficient reception of VHFLO, VHFHI, and UHF signals with reduced circuit complexity and size.
Implementation Method 1
The transformer includes a primary winding coupled to the output of the low noise amplifier and a secondary winding magnetically coupled to the primary winding
Implementation Method 2
The VHFLO portion of the tracking filter includes an inductive peaking circuit
Data Source
AI summary
A receiver includes a first amplifier, a first variable capacitor, and an inductance leg. The first amplifier has an input for receiving a radio frequency signal, and an output. The first variable capacitor has a first terminal coupled to the output of the first amplifier, a second terminal coupled to a power supply voltage terminal, and a control terminal for receiving a tuning signal. The inductance leg has a first terminal coupled to the output of the first amplifier, and a second terminal coupled to the power supply voltage terminal. The inductance leg includes a first inductor and has an effective resistance in series with the first inductor, wherein the effective resistance has a value related to an upper frequency threshold to be tuned by the receiver.