Common Oscillator Transceiver for Feedthrough and Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
WCDMA transceiver systems face challenges with transmitter feedthrough and high power consumption due to separate receiver and transmitter circuits, which often require additional filtering stages and power-hungry voltage-controlled oscillators.
Innovation Solution
Implementing a common receiver and transmitter oscillator, using an LC-based VCO for the first oscillator and a ring oscillator for the second, and incorporating a capacitor to filter out transmitter feedthrough signals, thereby eliminating the need for surface acoustic wave filters and reducing power consumption by sharing the oscillator across both circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separate receiver and transmitter circuits are implemented on different ICs, then interference between the two circuits is avoided, but device complexity and pin count increase
Solution Approach 1:
The patent merges the receiver and transmitter circuits onto a single integrated circuit chip, eliminating the need for separate ICs. This consolidation reduces device complexity and pin count while managing interference through shared oscillator design and filtering mechanisms.
Solution Approach 2:
The patent implements a common oscillator that serves dual functions for both the receiver and transmitter circuits. This universal oscillator design reduces the total number of oscillators needed, thereby simplifying the overall device structure and reducing pin count requirements.
2Object-affected harmful factors
If two separate filtering stages including SAW filter are implemented, then transmitter feedthrough is reduced, but device complexity and pin count increase
Solution Approach 1:
The patent combines the filtering function with the existing receiver circuitry by implementing a common oscillator shared between receiver and transmitter. This integration approach reduces the need for separate filtering stages including off-chip SAW filters, thereby reducing device complexity and pin count.
3Reliability
If separate voltage-controlled oscillators are implemented for receiver and transmitter, then circuit performance is optimized, but power consumption increases
Solution Approach 1:
The patent implements a common voltage-controlled oscillator that serves both the receiver and transmitter circuits. This single oscillator replaces what would traditionally require two separate VCOs, significantly reducing power consumption while maintaining the performance requirements for both communication directions.
4Device complexity
If receiver and transmitter are implemented on the same IC, then device complexity is reduced, but transmitter feedthrough increases
Solution Approach 1:
The patent merges receiver and transmitter on the same IC and uses a common oscillator to manage feedthrough. The shared oscillator design, combined with filtering mechanisms, allows both circuits to coexist on one chip while controlling the harmful feedthrough effect.
Solution Approach 2:
The common oscillator acts as an intermediary element that enables both receiver and transmitter operations on the same chip. By serving as a shared frequency source, it facilitates coordinated operation and enables filtering strategies to manage feedthrough while maintaining integration benefits.
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 reduces transmitter feedthrough without external filters and minimizes power consumption by using a shared oscillator, improving the overall efficiency and performance of the transceiver system.
Implementation Method 1
the first oscillator may provide a transmit frequency to a mixer in the transmitter circuitry to generate a transmitter RF signal. Furthermore, the first oscillator may also provide the transmit frequency to a first stage mixer in the receiver circuitry to down-convert a receiver RF signal from a receive frequency to an intermediate frequency (IF)
Implementation Method 2
the receiver circuitry may include a capacitor connected to an output of the first stage mixer. The capacitor may filter out unwanted transmitter feedthrough signals that leak into the receiver circuitry
Implementation Method 3
The receiver circuitry may further include a second oscillator and a second stage mixer. The second oscillator may provide an IF frequency to the second stage mixer to down-convert receiver signals at IF to a lower frequency
Data Source
AI summary
A transceiver system including a common receiver and transmitter oscillator. The transceiver system may include transmitter circuitry, receiver circuitry, and a first oscillator. The first oscillator may provide a transmit frequency to a mixer in the transmitter circuitry to generate a transmitter RF signal. Furthermore, the first oscillator may also provide the transmit frequency to a first stage mixer in the receiver circuitry to down-convert a receiver RF signal from a receive frequency to an intermediate frequency (IF). The receiver circuitry may include a second oscillator and a second stage mixer. The second oscillator may provide an IF frequency to the second stage mixer to down-convert receiver signals at IF to a lower frequency. The receiver circuitry may filter out transmitter RF feedthrough signals without using a SAW filter. The transmitter circuitry, the receiver circuitry, and the first oscillator may be included in a single IC.