PC-Based Annular Array

• Imaging and power/USB PCBs are 19cm (L) x 12CM (W) in size and may be mounted inside a PC enclosure using internal 12V DC supplies and USB data connection, or in an external enclosure using a 12V DC supply and USB cable
• Annular array B-mode, UBM and A-mode probe cable connectors at rear of card (integrated into card – no harnessing required)
• Optional battery operation available (up to three hours of continuous use per full charge)
• Includes SDK and basic software

Note: The included software is supplied to allow demonstration of the features of the sub-system, only. This software is not recommended for, nor is it suited to, clinical use of any kind.

Probe Support

The imaging engine supports 12MHz and 18MHz annular array probes, 35MHz and 50MHz single-channel UBM probes, and an A-mode probe.

High-voltage power supply (HVPS)

The HVPS provides voltage output of 12-100V. When coupled with CLI’s bipolar pulser (see below), this provides 200V peak-to-peak (maximum, using 50 Ohm load). Voltage level is under software control. Therefore, the actual voltage applied to the transducer can be determined by the developer/programmer and will depend on allowable power limits (i.e., mechanical index) for a given application, and other customer requirements.

Pulser / Receiver

The sub-system employs a novel pulser design that we call “Agile Pulse Technology”. APT produces a bi-polar pulse that can be optimized for probe frequencies ranging from 5-80MHz. This pulse shape is especially important when using transducers with frequencies in excess of 10.0 MHz where mono-polar “spike” pulses can often produce frequency spectra lower than expected. APT may also be used to drive the frequency lower, or higher, for a given transducer, producing the effect of a true multi-frequency probe.

Transmit focus is user selectable from 8 – 30mm depth, in real time. Dynamic receive focus is applied at each pixel from maximum depth to 8mm from the probe window, regardless of the transmit focal depth, and in real time. These features allow the use of larger-for-application transducers without sacrificing depth of field while achieving superior focusing.

The 12-bit receiver employs multi-tap bandpass filtering, rectification and high-speed sampling of the received waveform to provide accurate signal detection up to 50+ MHz. An RF amplifier provides a stable, low-noise signal that preserves all of the received data. Variable TGC for annular array imaging is applied in active mode, only. Digital filters are included in firmware that tailor certain receiver characteristics to the transducer frequency. A probe ID scheme allows the optimum digital and bandpass filters to be associated to particular probe types/frequencies. Other signal processing schemes are also possible through software upgrades.

Servo Controller

The servo controller has been designed to properly control CLI’s probes and to provide accurate position feedback to the imaging engine. CLI’s probe/servo combinations are typically accurate to within one degree (1º) of sweep angle. Final accuracy will be somewhat dependent on the total electronic stability of the host system and may exceed one degree.

Acoustic and position data are written to motherboard DRR (i.e., busmaster design) and may be streamed to memory for cine-mode recall, if supported in SW. Each image is drawn using 256 vectors and 8-bit grayscale. A wide variety of image geometries and displays may be formatted from this array and saved to disk in their raw format, including A/B-mode and A-mode displays. Saved images may later be recalled and displayed (individually or in cine mode). Images may be saved to the PC’s hard drive, to a peripheral drive, or transferred via LAN or internet to a central archive. Uncompressed images occupy 512 KB of disc space. Standard compression utilities (e.g., PKZIP, WINZIP, etc.) reduce file size to less than 150 KB.

CLI supplies Memory and scan conversion DLLs and sample source code for image generation and associated documentation for those wishing to develop custom end-user applications. Calls to DLLs include many features, such as:

• User-controlled variable focus control (8-30mm, 1mm steps)
• Dynamic receive focus (8mm-max depth)
• Selectable bandpass receive filters
• 4X oversampling
• One-way or two-way scanning
• Interpolation
• Frame averaging
• Cine (various lengths)
• Digital signal filtering
• Digital TGC and grayscale curves
• 256, 128, 64, or 32 vector imaging mode
• Various imaging widths and depths
• Selectable frame rates
• Selectable pulse frequencies
• Assumed speed of sound

Developers may also choose to develop their own scan conversion and DSP schemes, in which case only the use of CLI’s memory DLL is necessary.