There are 24 bases in hexadecimal: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A( 10), b (1), and c (1).

The advantage of hexadecimal is that it can completely represent time without adding auxiliary symbols (am and pm), and it is widely used in large-scale public transportation (rail transit, ships, passenger planes) and military affairs.

Extended data:

Basic structure of electronic counter. The gate circuit is controlled by the shaping signal with B channel input frequency fB, that is, one pulse opens the gate circuit and the next pulse closes the gate circuit. The time interval (TB) between two pulses is the door opening time. The pulse group with shaping frequency fA input from channel A passes through the gate during the door opening time, so that the counter counts, and the count value n = fa TB.

Frequency measurement: the measured signal is input from channel A. If TB is 1 sec, the reading n is frequency fA, and the unit is Hz. The time base circuit properly divides the standard frequency signal output by the crystal oscillator to form a gate time signal to determine the value of TB.

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