From GE Healthcare.;
'The System of Choice for Shared Service.
The LOGIQ® 7 system provides a full range of clinical applications including abdominal, small parts, surgery, vascular and cardiac imaging and the power of GE's patented TruScan architecture. Just imagine an ultrasound system so versatile and reliable that it can meet the demands of virtually any clinical setting. And an ergonomic design that improves scanning comfort and clinical work flow.'

From ESAOTE S.p.A.;
'The MyLab™30CV ultrasound system is an evolutionary step in ultrasound technology. Weighing less than 20 pounds, it is the first compact ultrasound system to deliver premium console performance. And with mobile, portable or stationary configurations, MyLab30CV can adapt to any clinical environment.'

According to Shannon's sampling theorem, the sampling frequency should be twice the frequency being sampled. The nyquist frequency is the maximum frequency that can be sampled without aliasing. In ultrasound imaging, it is defined as half of the pulse repetition frequency.
NF = PRF/2 (nyquist frequency = pulse repetition frequency/2)
This is the so-called Nyquist limit. If the velocity of flow exceeds the Nyquist limit, the direction and velocity are inaccurately displayed and appear to change direction. Color flow Doppler capitalizes on this effect. This allows detecting flow disturbances from laminar to turbulent flow.

See also Aliasing Artifact, Repetition Rate, and Sampling Rate.

The packet size is the number of sound bursts transmitted per color sector line. The accuracy of the estimated Doppler velocity is influenced by the packet size. A large packet size increases the accuracy of the mean flow velocity by decreasing the frame rate, the line density, or the sector angle.
Dwell time, ensemble length or packet size are synonymous.

Spectral analysis is the quantitative analysis method to display the distribution of frequencies. A difficult Doppler signal is separated into the frequency components so that the range of frequencies in a Doppler shifted signal can be analyzed. This allows measurement of blood flow velocity by positioning of a probing cursor in the artery (on the screen), and the signal representing blood flow velocity is generated. The peaks and ebbs create the spectrum, corresponding to systolic and diastolic blood flow. The signal is both visual and auditory.