MCQs on Digital Electronics

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01․ A computer has a word length of 8 bits (including sign). It is required to determine the range of integers that can be stored in the computer. If 1’s complement is used to represent the numbers, then the range will be
-256 to 256
-256 to 255
-127 to 127
-128 to 127

Since 1,s complement representation has a “negative zero” (11111111) in addition to zero (00000000), the values can be represented as (-27-1) to 27-1 i.e. -127 to 127

02․ While using a frequency counter for measuring frequency, two modes of measurement are possible. 1. Period time 2. Frequency mode There is a ‘cross-over frequency’ below which the period mode is preferred. Assuming the crystal oscillator frequency to be 4Mhz the crossover frequency is given by
8 Mhz
2 Mhz
2 Khz
1 Khz

As we know crossover frequency is the half of oscillator frequency. i.e. fcross - over = fcrystal/2 = 2Mhz