E7F Digital frequency divider circuits;
frequency marker generators;
frequency counters
E7F01
(D)
What is
the purpose of a prescaler circuit?
A. It converts the output of a JK flip-flop to
that of an RS flip- flop
B. It multiplies an HF signal so a
low-frequency counter can display the operating frequency
C. It prevents oscillation in a low-frequency
counter circuit
D. It divides an HF signal
so a low-frequency counter can display the operating frequency
E7F02
(B)
How
many states does a decade counter digital IC have?
A. 2
B. 10
C. 20
D. 100
E7F03
(A)
What is
the function of a decade counter digital IC?
A. It produces one output
pulse for every ten input pulses
B. It decodes a decimal number for display on a
seven-segment LED display
C. It produces ten output pulses for every
input pulse
D. It adds two decimal numbers
E7F04
(C)
What
additional circuitry is required in a 100-kHz crystal-controlled marker
generator to provide markers at 50 and 25 kHz?
A. An emitter-follower
B. Two frequency multipliers
C. Two flip-flops
D. A voltage divider
E7F05
(B)
If a
1-MHz oscillator is used with a divide-by-ten circuit to make a marker
generator, what will the output be?
A. A 1-MHz sinusoidal signal with harmonics
every 100 kHz
B. A 100-kHz signal with
harmonics every 100 kHz
C. A 1-MHz square wave with harmonics every 1
MHz
D. A 100-kHz signal modulated by a 10-kHz
signal
E7F06
(D)
What is
a crystal-controlled marker generator?
A. A low-stability oscillator that
"sweeps" through a band of frequencies
B. An oscillator often used in aircraft to
determine the craft's location relative to the inner and outer markers at
airports
C. A high-stability oscillator whose output
frequency and amplitude can be varied over a wide range
D. A high-stability
oscillator that generates a series of reference signals at known frequency
intervals
E7F07
(A)
What
type of circuit does NOT make a good marker generator?
A. A sinusoidal crystal
oscillator
B. A crystal oscillator followed by a class C
amplifier
C. A TTL device wired as a crystal oscillator
D. A crystal oscillator and a frequency divider
E7F08
(C)
What is
the purpose of a marker generator?
A. To add audio markers to an oscilloscope
B. To provide a frequency reference for a phase
locked loop
C. To provide a means of
calibrating a receiver's frequency settings
D. To add time signals to a transmitted signal
E7F09
(A)
What
does the accuracy of a frequency counter depend on?
A. The internal crystal
reference
B. A voltage-regulated power supply with an
unvarying output
C. Accuracy of the AC input frequency to the
power supply
D. Proper balancing of the power-supply diodes
E7F10
(C)
How
does a frequency counter determine the frequency of a signal?
A. It counts the total number of pulses in a
circuit
B. It monitors a WWV reference signal for
comparison with the measured signal
C. It counts the number of
input pulses in a specific period of time
D. It converts the phase of the measured signal
to a voltage which is proportional to the frequency
E7F11
(A)
What is
the purpose of a frequency counter?
A. To indicate the frequency
of the strongest input signal which is within the counter's frequency range
B. To generate a series of reference signals at
known frequency intervals
C. To display all frequency components of a
transmitted signal
D. To compare the difference between the input
and a voltage-controlled oscillator and produce an error voltage