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Modern radars generally perform all of these MTI techniques as part of a wider suite of signal processing being carried out by digital signal processors. MTI may be specialized in terms of the type of clutter and environment: airborne MTI (AMTI), ground MTI (GMTI), etc., or may be combined mode: stationary and moving target indication (SMTI).
Pulse-Doppler typically uses medium pulse repetition frequency (PRF) from about 3 kHz to 30 kHz. The range between transmit pulses is 5 km to 50 km. Range and velocity cannot be measured directly using medium PRF, and ambiguity resolution is required to identify true range and speed.
Pulse compression is a signal processing technique commonly used by radar, sonar and echography to either increase the range resolution when pulse length is constrained or increase the signal to noise ratio when the peak power and the bandwidth (or equivalently range resolution) of the transmitted signal are constrained.
Range ambiguity resolution is a technique used with medium pulse-repetition frequency (PRF) radar to obtain range information for distances that exceed the distance between transmit pulses. This signal processing technique is required with pulse-Doppler radar. [1] [2] [3]
The ability to counter steep diving missiles was improved with more energy at higher elevations or longer pulse. [ 5 ] : 316–317 SPY-1B(V) is a development of earlier SPY-1B with moving target indication capability incorporated in 1997.
The ABPI test is a popular tool for the non-invasive assessment of Peripheral vascular disease (PVD). Studies have shown the sensitivity of ABPI is 90% with a corresponding 98% specificity for detecting hemodynamically significant (stenosis of more than 50%) in major leg arteries, defined by angiogram. [3] However, ABPI has known issues:
The Paraná maneuver makes use of a proprioceptive reflex to test venous-muscle-pump- induced flow. (A proprioceptive reflex is a response to a perceived stimulus, especially with regard to movement and position of the body.) [ 19 ] A slight push to the waist triggers a muscle contraction in the leg to maintain posture.
On inspection the clinician looks for signs of: trauma; previous surgery ()muscle wasting/muscle asymmetry; edema (swelling) erythema (redness); ulcers – arterial ulcers tend to be on the borders / sides of the foot, neuropathic ulcers on the plantar surface of the foot, venous ulcers tend on be on the medial aspect of the leg superior to the medial malleolus.