1. What type of filter produces a predictable phase shift characteristic in all frequencies?
a) Band pass filters
b) High pass filters
c) Low pass filters
d) All pass filters
Explanation: An all pass filter passes all frequencies equally well over its design range but has a fixed or predictable phase shift characteristic. Filters normally attenuate the signal applied for some values of frequency whereas an all pass filter retains the signal level at all frequencies.
2. An RC coupling circuit is an example of what type of filter?
a) Low pass filter
b) High pass filter
c) Band pass filter
d) All pass filter
Explanation: An RC coupling circuit is an example of a high-pass filter because the AC component of the input voltage is developed across R and the DC voltage is blocked by the series capacitor. Furthermore, with higher frequencies in the AC component, more AC voltage is coupled.
3. Find the cut off frequency for an RC low pass filter of R=8.2Ω and C=0.0033μF?
a) 6KHz
b) 5.88KHz
c) 4.26KHz
d) 7.91KHz
Explanation:
4. What is the value of resistor for a high pass RC filter to produce a cutoff frequency of3.4KHz if C = 0.047μF?
a) 654Ω
b) 1000Ω
c) 996Ω
d) 752Ω
Explanation:
5. Notch filters and band reject filters are the same.
a) True
b) False
Explanation: Notch filters are also referred to as bandstop or band reject filters. Band-reject filters are used to greatly attenuate a narrow range of frequencies around a center point. Notch filters accomplish the same purpose, but for a single frequency
6. What is the value of notch frequency if the values of resistance and capacitance are 100 kV and 0.02 μF?
a) 79.6Hz
b) 21.5Hz
c) 82.4Hz
d) 40Hz
Explanation:
7. What is the loss the filter introduces to the signals in the passband called?
a) passband loss
b) Insertion loss
c) Attenuation
d) Degradation
Explanation: Insertion loss is the loss the filter introduces to the signals in the passband. Passive filters introduce attenuation because of the resistive losses in the components. Insertion loss is typically given in decibels
8. The attenuation rate is also called?
a) Roll off
b) Roll in
c) Envelope delay
d) Ripple
Explanation: Roll off is also called the attenuation rate, roll-off is the rate of change of amplitude with frequency in a filter. The faster the roll-off, or the higher the attenuation rate, the more selective the filter is, i.e., the better able it is to differentiate between two closely spaced signals, one desired and the other not.
9. A sine wave whose frequency is some integer multiple of a fundamental sine wave is called?
a) Complex wave
b) Square wave
c) Harmonic
d) Digital pulses
Explanation: A harmonic is a sine wave whose frequency is some integer multiple of a fundamental sine wave. The third harmonic of a 2-kHz sine wave is a sine wave of 6 kHz
10. What is the duty cycle of a square wave with equal duration positive and negative alterations?
a) 100%
b) 50%
c) 200%
d) 25%
Explanation: Duty cycle is the ratio of the duration of the positive alteration t1 to the period T expressed as percentage. D= t1⁄T*100 = t1⁄2t1 * 100 = 50%.