# Which one of the following function qualifies to be an autocorrelation function of a real valued time signal

1.  sin(ωt)

2.  exo(-t)

3.  ∂(t)

4.  u(t)

4

∂(t)

Explanation :
No Explanation available for this question

# The auto-correlation function of white noise is

1.  a delta function

2.  a constant

3.  gaussian

4.  exp (-|t|) with tumid notation

4

a delta function

Explanation :
No Explanation available for this question

# The spectral density of white noise is

1.  Exponential

2.  Uniform

3.  Poisson

4.  Gaussian

4

Uniform

Explanation :
No Explanation available for this question

# An RC-coupled amplifier is assumed to have a single pole low frequency transfer function. The maximum lower cutoff frequency allowed for the amplifier to pass50hz square wave with not more than 10% tilt is

1.  1Hz

2.  1.59HZ

3.  1 KHZ

4.  1. 59 KHZ

4

1.59HZ

Explanation :
No Explanation available for this question

# A power amplifiers delivers 50W output at 50% efficiency. The ambient temperature is 250C. If maximum allowable junction temperature is 1500C, then thermal resistance θjc that can be tolerated is

1.  250C/W

2.  200C/W

3.  50C/W

4.  10C/W

4

50C/W

Explanation :
No Explanation available for this question

# An amplifier has an open loop gain of 100 and its lower and upper cutoff frequency of 100 Hz and 100kHz, respectively. A feed back network with a feedback factor of 0.99is connected to the amplifier. The new lower and upper cutoff frequencies are at

1.  fH=10MHz and fL=1 Hz

2.  fH=25MHz and fL=10 Hz

3.  fH=100MHz and fL=100 Hz

4.  fH=10 MHz and fL=10 Hz

4

fH=10MHz and fL=1 Hz

Explanation :
No Explanation available for this question

# In a bipolar transistor at room temperature, if emitter current is doubled, then voltage across its base emitter junction

1.  Doubles

2.  Halves

3.  Increases by about 20mV

4.  Decreases by about 20 mV

4

Increases by about 20mV

Explanation :
No Explanation available for this question

# A npn transistor has a beta cutoff frequency fβ of a 1 MHz, and common emitter short circuit low frequency current gain frequency fr and alpha cutoff frequency fα respectively are

1.  200MHz, 201MHz

2.  200 MHz, 199 MHz

3.  199 MHz, 200 MHz

4.  201 MHz, 200 MHz

4

200MHz, 201MHz

Explanation :
No Explanation available for this question

# In a differential amplifier, CMRR can be improved by using an increased

1.  Emitter resistance

2.  Collector resistance

3.  Power supply voltages

4.  Source resistance

4

Emitter resistance

Explanation :
No Explanation available for this question

1.  1.42

2.  1.62

3.  1.62

4.  1.72

4