Technology Management Group
TEC Edmonton – University of Alberta
Posted: December 25, 2014
Coded excitation is widely used in ultrasound, radar, sonar and other imaging systems as well as in communication systems. Coded excitation involves the transmission of long-duration pulses with a time-bandwidth product (TBP) greater than 1. By coding the pulse on transmission, the received signals may be processed to compress (decode) the effective impulse response, and thus restore spatial resolution. If decoding is successful, signal to noise ratio (SNR) is amplified. If decoding is incomplete, the signal remains partially distributed spatially, producing range lobes that reduce signal contrast thus negating the advantages of coded excitation. Moreover, coded excitations are typically transmitted in sequence rather than in parallel rendering it deficient for high frame rate imaging.
Researchers at the University of Alberta have developed sets of codes such that different codes can be transmitted simultaneously on a set of transducer elements or transmitters, received in parallel from a set of receivers and decoded for each transmit code such that there is minimal interference between received signals after decoding. Typically, transmission through multiple transmitters requires N transmit events for N transducer elements. In contrast, our researchers’ proposed method requires only a single transmit event, but with different coded signals sent from each element during one transmit event. Depending on the application, the signal at the receiver can be decoded by using a comparing algorithm such as correlation. Such codes and signal acquiring algorithms provide advantages over other methods by significantly reducing signal interference and increasing SNR, resulting in high contrast and high resolution images. This technique could be particularly valuable for high‐frame rate imaging and 3D imaging.
- Increased SNR
- Increased spatial resolution
- Increased image contrast
- High-frame-rate imaging and 3D imaging
The invention represents a valuable opportunity in enhancing ultrasound, radar, sonar and other imaging systems as well as in communication systems.