Analog signals are continuous in both time and value. Analog signals are used in many systems, although the use of analog signals has declined with the advent of cheap digital signals. Digital signals are sampled, quantized & encoded version of continuous time signals which they represent.
Causes of Tingling in the Hands and Feet. Diabetes is one of the most common causes of peripheral neuropathy, accounting for about 30% of cases. In diabetic neuropathy, tingling and other symptoms often first develop in both feet and go up the legs, followed by tingling and other symptoms that affect both hands and go up the arms. About two-thirds of people with diabetes have mild to severe forms of nerve damage.
Tingling hands, feet, or both is an extremely common and bothersome symptom. Such tingling can sometimes be benign and temporary. For example, it could result from pressure on nerves when your arm is crooked under your head as you fall asleep. Or it could be from pressure on nerves when you cross your legs too long. In either case, the pins and needles effect -- which is usually painless -- is soon relieved by removing the pressure that caused it. In many cases, however, tingling in the hands, feet, or both can be severe, episodic, or chronic.