Question 1

Figure 4 A test of a filter using an oscilloscope
-Refer to Figure 4. The signal on the X channel of the oscilloscope is a(n)
A)sawtooth
B)continuous frequency sinusoidal wave
C)amplitude modulated frequency
D)constant amplitude swept frequency

Accepted Answer

The signal on the X channel of the oscilloscope is a sawtooth because it is a repeating waveform that has a sharp rise and a gradual fall.

Question 2

The critical frequency of a high- pass filter is where the response is
A)-20 dB from the passband response
B)at its highest point
C)-3 dB from the passband response
D)-6 dB from the passband response

Accepted Answer

The critical frequency of a high-pass filter (also known as the cutoff frequency) is defined as the frequency at which the output signal's power is reduced to half of the power of the input signal. This corresponds to a -3 dB point from the passband response, because a decrease of 3 dB represents a halving of power.

Question 3

A high Q bandpass filter
A)can reject a specific frequency
B)has a narrow bandwidth
C)is usually constructed from cascaded low- pass and high- pass filters
D)all of the above

Accepted Answer

A high Q bandpass filter is characterized by its narrow bandwidth, which allows it to select or pass a narrow range of frequencies while rejecting frequencies outside this range. Choices A and C describe other types of filters or filter constructions but do not accurately describe the properties of a high Q bandpass filter.

Question 4

Figure 1 Stage 1: DF = 1.848 and RS1U1B11S1U1B0/RS1U1B12 S1U1B0= 0.152; stage 2: DF = 0.765 and RS1U1B13S1U1B0/RS1U1B14 S1U1B0=1.235.
-Refer to Figure 1 with values as given. R3 should have a value of
A)1.8 k▲
B)1.5 k▲
C)1.2 k▲
D)none of the above

Accepted Answer

Without the specific values or a description of Figure 1, it's impossible to accurately determine the value of R3. Calculations for resistor values typically depend on the context of the circuit, such as whether resistors are in series or parallel, and the total voltage or current in the circuit.

Question 5

The biquad filter has
A)a summing amplifier, an inverting amplifier, and an integrator
B)an inverting amplifier and two differentiators
C)a summing amplifier and two differentiators
D)an inverting amplifier and two integrators

Accepted Answer

A biquad filter typically consists of an inverting amplifier and two integrators, which are used to achieve a second-order filter response. This configuration allows for the implementation of various filter types (low-pass, high-pass, band-pass, etc.) with precise control over the filter's frequency and quality factor.

Question 6

Figure 1 Stage 1: DF = 1.848 and RS1U1B11S1U1B0/RS1U1B12 S1U1B0= 0.152; stage 2: DF = 0.765 and RS1U1B13S1U1B0/RS1U1B14 S1U1B0=1.235.
-Refer to Figure 1 with values as given. R1 should have a value of
A)1.2 k▲
B)1.8 k▲
C)1.5 k▲
D)none of the above

Accepted Answer

The answer of  Figure 1 Stage 1: DF =...

Question 7

Figure 5 Response curve for three different filters
-Refer to Figure 5. The response labeled "A" represents a
A)Butterworth response
B)Bessel response
C)Chebyshev response
D)none of the above

Accepted Answer

The answer of  Figure 5 Response curve for three...

Question 8

A low- pass filter has a critical frequency of 10 kHz. The bandpass is
A)20 kHz
B)5.0 kHz
C)15 kHz
D)10 kHz

Accepted Answer

The bandpass of a low-pass filter refers to the range of frequencies it allows to pass through without attenuation, which extends from DC (0 Hz) up to its critical frequency. Therefore, for a low-pass filter with a critical frequency of 10 kHz, the bandpass is 10 kHz.

Question 9

Figure 5 Response curve for three different filters
-Refer to Figure 5. The response labeled "B" represents a
A)Butterworth response
B)Bessel response
C)Chebyshev response
D)none of the above

Accepted Answer

The response labeled "B" represents a Bessel response, which is characterized by its maximally flat group delay, ensuring that all frequency components of the signal are delayed by approximately the same amount, preserving the waveform shape of the signal being filtered. This is distinct from Butterworth (maximally flat magnitude response) and Chebyshev (ripples in the passband or stopband) responses.

Question 10

Figure 2 Note that the capacitors have different values.
-Refer to Figure 2. The fc for the first section is
A)800 Hz
B)160 Hz
C)80 Hz
D)1.6 kHz

Accepted Answer

The answer of  Figure 2 Note that the capacitors...

Question 11

Figure 3
-Refer to Figure 3. This type of filter is called a
A)biquad filter
B)Sallen- Key filter
C)multiple- feedback filter
D)state- variable filter

Accepted Answer

The answer of  Figure 3
-Refer to Figure 3. This...

Question 12

The bandwidth of a bandpass filter is measured at
A)the -2 dB frequencies
B)the -6 dB frequencies
C)the -4 dB frequencies
D)none of the above

Accepted Answer

The bandwidth of a bandpass filter is typically measured at the -3 dB frequencies, which is not listed among the options.

Question 13

The best response to use for pulses is
A)Butterworth response
B)Bessel response
C)Chebyshev response
D)none of the above

Accepted Answer

Bessel filters are best suited for pulse applications because they provide the best pulse response with minimal distortion, preserving the shape of the waveform.

Question 14

A basic one- pole RC low- pass filter has fc = 5.9 kHz using a 0.01 µF capacitor. The resistor value is
A)2.7 k▲
B)1.6 k▲
C)16 k▲
D)270 ▲

Accepted Answer

The cutoff frequency of a one-pole RC low-pass filter is given by fc = 1/(2πRC). Solving for R, we get R = 1/(2πfcC) = 1/(2π(5.9 kHz)(0.01 µF)) = 2.7 kΩ.

Question 15

Figure 1 Stage 1: DF = 1.848 and RS1U1B11S1U1B0/RS1U1B12 S1U1B0= 0.152; stage 2: DF = 0.765 and RS1U1B13S1U1B0/RS1U1B14 S1U1B0=1.235.
-Refer to Figure 1. Assume Vin = 1.0 Vpp sine wave at 20 kHz. At this frequency, Vout is approximately
A)1.0 Vpp
B)10 mVpp
C)1.0 mVpp
D)100 µVpp

Accepted Answer

The answer of  Figure 1 Stage 1: DF =...

Question 16

Figure 2 Note that the capacitors have different values.
-Refer to Figure 2. Assume the capacitors in section 1 are made larger. This change will
A)decrease the bandwidth
B)increase the bandwidth
C)not affect the bandwidth

Accepted Answer

Increasing the capacitance of the capacitors in section 1 will increase the time constant of the circuit, which in turn will increase the bandwidth.

Question 17

Figure 4 A test of a filter using an oscilloscope
-Refer to Figure 4. The block with the ? on it represents a
A)low- pass filter
B)impedance matching circuit
C)detector
D)amplifier

Accepted Answer

A detector in a circuit diagram is often represented by a block with a question mark, as it is responsible for demodulating or detecting the signal from its modulated form.

Question 18

Figure 3
-Refer to Figure 3. An advantage of this type of filter is that it
A)the low and high- pass outputs are equivalent to a 4- pole filter
B)can be optimized for all three outputs
C)the bandpass output can have a very high Q
D)all of the above

Accepted Answer

The answer of  Figure 3
-Refer to Figure 3. An...

Question 19

Assume a high- pass filter and a low- pass filter are cascaded to form a band- pass filter. The upper cutoff frequency will be determined by
A)the high- pass filter
B)answer depends on the order of the filters
C)the low- pass filter
D)none of the above

Accepted Answer

The upper cutoff frequency of a band-pass filter, formed by cascading a high-pass and a low-pass filter, is determined by the low-pass filter. This is because the low-pass filter limits the high-frequency components that can pass through, thus setting the upper frequency limit of the band-pass filter.

Question 20

Figure 4 A test of a filter using an oscilloscope
-Refer to Figure 4. The input signal to the filter (Vin)is a(n)
A)continuous frequency sinusoidal wave
B)amplitude modulated frequency
C)constant amplitude swept frequency
D)sawtooth

Accepted Answer

The term "constant amplitude swept frequency" refers to a signal where the frequency changes over time but the amplitude remains constant. This is typical for signals used in frequency response tests or sweeps, where the input signal's frequency is gradually increased or decreased while maintaining a constant amplitude to analyze the system's or filter's response across a range of frequencies.

Quiz 15: Active Filters

Figure 4 A test of a filter using an oscilloscope -Refer to Figure 4. The signal on the X channel of the oscilloscope is a(n)

The critical frequency of a high- pass filter is where the response is

A high Q bandpass filter

Figure 1 Stage 1: DF = 1.848 and R₁/R₂= 0.152; stage 2: DF = 0.765 and R₃/R₄=1.235. -Refer to Figure 1 with values as given. R3 should have a value of

The biquad filter has

Figure 1 Stage 1: DF = 1.848 and R₁/R₂= 0.152; stage 2: DF = 0.765 and R₃/R₄=1.235. -Refer to Figure 1 with values as given. R1 should have a value of

Figure 5 Response curve for three different filters -Refer to Figure 5. The response labeled "A" represents a

A low- pass filter has a critical frequency of 10 kHz. The bandpass is

Figure 5 Response curve for three different filters -Refer to Figure 5. The response labeled "B" represents a

Figure 2 Note that the capacitors have different values. -Refer to Figure 2. The fc for the first section is

Figure 3 -Refer to Figure 3. This type of filter is called a

The bandwidth of a bandpass filter is measured at

The best response to use for pulses is

A basic one- pole RC low- pass filter has fc = 5.9 kHz using a 0.01 µF capacitor. The resistor value is

Figure 1 Stage 1: DF = 1.848 and R₁/R₂= 0.152; stage 2: DF = 0.765 and R₃/R₄=1.235. -Refer to Figure 1. Assume Vin = 1.0 Vpp sine wave at 20 kHz. At this frequency, Vout is approximately

Figure 2 Note that the capacitors have different values. -Refer to Figure 2. Assume the capacitors in section 1 are made larger. This change will

Figure 4 A test of a filter using an oscilloscope -Refer to Figure 4. The block with the ? on it represents a

Figure 3 -Refer to Figure 3. An advantage of this type of filter is that it

Assume a high- pass filter and a low- pass filter are cascaded to form a band- pass filter. The upper cutoff frequency will be determined by

Figure 4 A test of a filter using an oscilloscope -Refer to Figure 4. The input signal to the filter (Vin) is a(n)