TATA ELxsi Placement Paper

Company: Tata Elxsi

(1)problem on lissojous pattern: in x-y mode if vlg applied to x-axis is 2 sinwt then what is the vtg to be applied to y-axis so that we observe the following pattern on the cro : [angle b/n x-axis and the diagonal line is 45degrees] ans is 2root 2 sin (wt +45)

(2)what is the resolution of an adc : vref/(2 pow n).
(3)some circuit is given with two f/f s ,what is that circuit? Ans may be shift reg
(4)spatial to temporal converter is ? (a) shift reg ( b) counter (c ) adc ans may be adc
(5) darlington is used for _____ ans high current gain
(6)some circuit with nand gates is given ,what is that circuit ans is xor
(7) a wired circuit with some nand gates is given asked the function of that circuit
(8) an opamp circuit is given asked to find the transfer function of it ( I think its an ideal integrator circuit)
(9)a pole zero pattern of an impedance function is given . it has a conjugate pair of zeros and a conjugate pair of poles ,then what elements does the impedance consists of? Ans LC elements
(10)most computers wont use floating point arithmetic .why?
a.costly b. slow c. cant
(11)bit-slice processor mean …… ans used for shift ,masking of bits
(12)tv resolution depends on a. bandwidth 2. detector c. no. of frames /sec
(13)equalizing pulses are sent in tv during a. horizontal blanking b. vertical blanking ……….
(14)cdma is not suitable for satellite communication . why ? ans may be complexity of operation
(15)ac motor used in servo applications is (a) single phase induction b.2 phase induction c. 3 phase induction
(16)given some waveforms and asked that which of the waveforms will have odd harmonics of sine terms
(17)asked for two’s complement of a number
(18)maximum signed no. represented by a 8 bit computer
(19)a chip has a capacity of 256bits,to implement a 1KB capacity how many chips are required ans 32
(20)ecl operates in ____ and ____ regions of the transistor
(21)given a transient circuit ,asked for time constant while charging and discharging
1. it can store a bit 2. jk f/f have rat race when storing a 2 bit info 3. master slave is used to store a 2 bit info
4. d f/f used as a latch for multiplexing operations
(23) Venn diagram is given and asked to write expression for the shared portion in it
(24)cb and ce are ____ biased when transistor is in saturation
(25) a problem on cro and probe interface i.e design of an attenuator for the cro probe
(formula for it is R1 * c1 = R2 * C2 )
(26) condition for nyquist rate .
(27)carry look ahed adder is 1.fast 2. requires more h/w 3. costly
(28) ideal power supply will have a. zero internal resistance b. more o/p resistance c. less o/p resistance

TATA ELxsi Placement Paper