Self-tuning crystal notch filter
US6047601A · kind A · utility
Inventor
Key dates
| Filing date | Jan 23, 1998 |
| Grant date | Apr 11, 2000 |
| Priority date | — |
| Expiry date | Jan 23, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S600/921
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A self-tuning crystal notch filter suitable for rejecting a carrier signal in a receiver channel of a receiver of an ultrasound imaging system. The crystal notch filter has a resonant frequency which is electronically tuned. Tuning is done under software control without operator intervention. The software instructs a channel other than the one being tuned to transmit into the transducer. The receive channel being tuned amplifies the received signal and then passes the amplified signal through the notch filter and the TGC amplifier to the corresponding digital signal processing (DSP) circuit via an analog-to-digital converter. The software reads the amplitude of the digital receive signal output from the DSP circuit. By programming a D/A converter incorporated in the notch filter, a value can be found that minimizes the amplitude of the signal output by the DSP circuit, i.e., maximizes the amount of carrier signal being rejected. This value is then used during subsequent imaging data acquisition. This notch filter tuning operation is performed for the respective notch filter in each receive channel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.