Signal Generator Bandwidth Extension via Coupler-Filter Cascades

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Solution Overview

Problem

Current broadband signal-generator architectures using switched filters face limitations such as signal attenuation and restricted frequency bandwidth, especially when operating in the millimeter-wave spectrum, leading to decreased dynamic range and limited operating bandwidth.

Innovation Solution

The use of coupler-filter cascades between transmission lines replaces switched filters, reducing signal attenuation and component complexity, and extending the operating bandwidth by splitting the frequency spectrum into multiple bands, with coupler transmission lines and optional switches to isolate and couple desired frequencies effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If switched filters are used along the transmission line to extend operating frequency bandwidth, then the frequency bandwidth is extended, but signal attenuation increases and dynamic range decreases

Engineering Contradiction:

Improveoperating frequency bandwidthVSAvoidsignal attenuation

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent removes the switched filter component from the signal path entirely, replacing it with a direct connection between the low-frequency signal generator and the output. This extraction eliminates the source of signal attenuation while preserving the frequency bandwidth extension capability through alternative means.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an upconverter as an intermediary device that converts the low-frequency signal to the desired high-frequency output signal. This mediator allows the system to achieve wide frequency bandwidth without requiring switched filters in the signal path, thereby avoiding signal attenuation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If switched filters are used to filter output signals, then frequency-band filtering is implemented, but device complexity increases

Engineering Contradiction:

Improvefrequency-band filtering capabilityVSAvoidcomponent complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the switched filter assembly from the system, eliminating the complexity associated with multiple filters, switch matrices, and their interconnections. The frequency-band filtering function is replaced by the natural frequency-selective properties of the upconversion process.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical switched filter system with an electronic upconversion process. Instead of physically switching between filters, the system uses frequency conversion to achieve the same functional result with simpler electronic components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If the operating frequency range extends into the millimeter-wave spectrum, then frequency bandwidth is extended, but RF switch limitations cause severe performance degradation

Engineering Contradiction:

Improveoperating frequency rangeVSAvoidsignal generator performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of attempting to switch high-frequency millimeter-wave signals through filters (which causes performance degradation), the patent inverts the approach by generating low-frequency signals and then upconverting them to the desired high-frequency range. This avoids the fundamental limitation of RF switches at millimeter-wave frequencies.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The upconverter serves as an intermediary that bridges the gap between the low-frequency signal generator and the high-frequency output requirement. This mediator enables the system to achieve millimeter-wave operating frequencies without subjecting the signal path to the limitations of high-frequency switches.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8027390B2Method and system to extend a useable bandwidth of a signal generator

Publication Date: 2011.09.27 ANRITSU CO

AI summary

A system to extend an operating bandwidth of a signal generator comprises a signal generator, an output port, a first transmission line extending between the signal generator and the output port, a mixer adapted to receive a first signal from the signal generator, a local oscillator adapted to provide a second signal to the mixer to beat against the first signal, a second transmission line extending from the mixer to transmit a plurality of output signals of the mixer, and one or more channels couplable between the first transmission line and the second transmission line. The one or more channels include a first coupler having a length adapted to couple one or more of the output signals within a band of frequencies from the second transmission line to the channel, a second coupler having a length adapted to couple the one or more of the output signals from the channel to the first transmission line, and a filter arranged between the first coupler and the second coupler.