Which type of signal is has a step-like appearance because it is composed of precise values of "this or that" with nothing between them? Options:

Digital signals

Dial-up internet

Vinyl records

Analog signals

6–43 a food department is kept at 2128c by a refrigerator in an environment at 308c. the total heat gain to the food department is estimated to be 3300 kj/h and the heat rejection in the condenser is 4800 kj/h. determine the power input to the compressor, in kw and the cop of the refrigerator.