The ideal bandwidth allows the signal to pass under conditions of maximum AM or FM adjustment. In FM, radio frequency signal bandwidth is determined by the frequency deviation of the signal. A standard mercury barometer has a glass column about 30 inches long, closed at one end, with a mercury-filled reservoir. Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir. High atmospheric pressure forces the mercury higher in the column.
Low pressure allows the mercury to drop to a lower level in the column.
An aneroid barometer uses a small, flexible metal box called an aneroid cell. The box is tightly sealed after some of the air is removed, so that small changes in external air pressure cause the cell to expand or contract. A substance that forms a salt when it reacts with acid. The speed in baud is the number of discrete conditions or signal events per second. If each signal event represents only one bit condition, baud is the same as bits per second.