Created it, 06/02/21

Last update it, 06/02/21

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Answers 9      Answers 10      Answers 11     Answers 12    

Answers to the test N° 9

1°) Not, the binary and decimal addition can be carried out while following the same procedure. It is necessary to add the figures column by column from right to left by taking account of possible reserves.

2°) The sum of two binary digits is carried out by a door OR Exclusive and reserve by a door AND.

3°) It is called half-adder.

4°) The complete summoner has three entries: two for the terms of the sum and for reserve.

5°) It is an English term which means going beyond. By this term, one indicates that the summoner produced a result higher than the capacity of the register.

6°) The highest computing speed is obtained with the circuit of nap in parallel with anticipated reserve.

7°) It is necessary to use four integrated circuits standard 7485 to compare two numbers of 16 bits (16 / 4 = 4).

8°) A multiplexer with 6 ways requires three entries of selection since 2² < 6 £ 2³.

Answers to the test N° 10

1°) the register with shift is a device equipped with memory as the rocker and the switch which can memorize permanently a state 1 or 0. The memories themselves, used in the computers, are distinguished from the registers by their greater capacity.

2°) the capacity of a memory is expressed by indicating the maximum capacity of information which this memory can preserve. Information is generally expressed out of bits or multiples : kilobit (1 024 bits) or megabit. In the case of the memories usually, information (thus storage capacity) is expressed in kilooctets whose symbol is K.

3°) Access chance means that each addressable site of the memory is accessible directly, some that is its position.

4°) RAM means random access memory (Random Access Memory).

5°) ROM means memory with reading only authorized (Read Only Memory).

6°) the ROM as the RAM can be random access memories. Generally, the electronic ROM are of the “RAM of the ROM type”, i.e. RAM in which only the reading is possible ; this denomination, although correct and logical, is however not current.

7°) the address of the site of memory intended for one Byte is a combination of bits, usually applied to the entries of a decoder with which one selects the desired site.

8°) the symbol used is R / W (R = Read, lira and W = Write, to write).

9°) the static storage stores the information during an unlimited time (in the RAM, as long as the food or until its obliteration lasts ; in the ROM, as long as the physical support is not destroyed).

The dynamic storage stores the information during a limited time and makes periodically necessary an operation of cooling.

10°) the static cell storage is primarily made up of a rocker ; that of the dynamic storage is consisted a switch MOS coupled to a condenser.

11°) the speed of a memory is characterized by the access time and the cycle time.

12°) the time cycle is the duration of the interval of time which must pass between two successive requests for reading or writing in memory.

13°) the memory is volatile when it loses its contents at the time of a power supply cut-off.

14°) the principal types of electronic memories are :

- Static storages (the information is stored as much as it is not erased and as long as the supply is not cut off).

- Dynamic storages (information is regenerated periodically).

They can be still classified in :

• RAM (with chance access and read / write).

• ROM (with chance access and reading only).

• CCD (with access series)..

• Magnetic core memories.

• Magnetic bubble memories.

The ROM memories are subdivided in ROM memory simple, PROM, EPROM or REPROM, EEPROM or E²PROM.

Memory with mechanical drive :

• Paper medium including/understanding tapes and punch cards.

• Magnetic medium, tapes, cassettes, diskettes.

• Optical disc.

Answers to the test N° 11

1°) the capacity of matrix of a PLA is the product of the number of doors AND making it possible to carry out the mintermes by the number of doors OR making it possible to carry out the sum of the mintermes. This capacity is expressed out of bits.

2 - a) F1 = I01 + I0 I1

         F2 = 01 + I0 I1

         F3 = 01 + I0 I1

Like F2 = F3, it is enough to generate two functions and not three

2 - b) 

3°) It is first of all necessary to determine the minimal period of the clock compatible with the operation of the numerical system.

It is necessary for that to make the sum of all the travel times through each logical door and to add to it the time of presetting for the rockers (Set up time).

Then one calculates : Fmax = 1 / Tmin.

4°) the typical value is the average value of the maximum frequencies of operation for a whole whole of components (mass production).

The minimal value is smallest of the values of maximum frequency of clock for the whole of the components. With this minimal value, one is certain that all the components function correctly.

5°) CLOCK SKEW is the phenomenon of shift of clock. It appears when the same initial clock signal subdivides and follows two different ways for example.

6°) It is necessary to introduce a resistance of 10 KW so that the logical levels L and H are correct on entry CMOS. (See the diagram below)

Answers to the test N° 12

1°) 11 / 16 de VR = 11 volts

2°) VA = 255 / 256 of VR = (16 x 255) / 256 = 15,9375 volts

3°) The principal characteristics of an operational amplifier are : infinite amplification, impedance of infinite entry, null output impedance.

4°) Amplification in tension AV = - (R2 / R1) = - 100 / 5 = - 20

5°) The resolution corresponds to the increase in the analogical tension, caused by the increase in a unit of the binary number of entry. The absolute resolution depends on the number of bits of entry.

6°) The precision of the converters is affected by : offset not no one, error of transfer, non-linearity.

7°) One needs 15 comparators (16 combinations minus one).

8°) The parallel converters A / D are very fast

9°) V = VR / (2ⁿ x tconv) = 10 (2⁸ x 10^-5) = 3906 V / s

10°) The circuit “Sample And Hold” makes it possible to stabilize the tension to be converted throughout all conversion.

11°) A converter with slope includes/understands : a circuit RC associated with a switch, a comparator, a control circuit and a meter.

12°) The converters with simple slope are not very precise in particular because of the condenser C. In a converter with double slope, the precision depends very little on the condenser C and it is better than in the first case. 

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Daniel