Attempt all the questions. There is only one correct answer to each question. Click show all questions. When you have completed the quiz press the back button to return your last page.
In a PLL frequency synthesiser which of these parts is responsible for changing the frequency?
The reference oscillator
The fixed divider
The phase detector
The programmable divider
In a PLL frequency synthesiser the part responsible for generating the output frequency is
The phase detector
The fixed divider
The voltage controlled oscillator
The loop filter
In a PLL frequency synthesiser the part responsible for the step sizes is
The fixed divider
The programmable divider
The phase detector
The loop filter
In a PLL frequency synthesiser the part responsible for comparing the input from the fixed divider and the input from the programmable divider is
The loop filter
The VCO
The phase detector
The reference oscillator
In a PLL frequency synthesiser what is the purpose of the out of lock output
To prevent reception when the oscillator is not stabilised
To prevent transmissions when the oscillator is not stabilised
To alter the step size
To show the loop filter is not working
In a direct digital synthesiser the phase accumulator receives inputs about
Clock signals and the low pass filter
Clock signals and phase increments
Output frequency and phase increments
Output frequency and the waveform map
The purity of a DDS signal can be improved by
Increasing phase increments
Widening the low pass filter
Increasing the number of bits used to represent a sine wave
Decreasing the number of bits used to represent a sine wave
In a DDS which of these would not be used to store a waveform map
PROM
ROM
Transistor
PIC
Which of these is false when using a synthesiser in canalised FM transceivers
Synthesisers are cheaper than using individual crystals for each channel
Synthesisers have a lower noise output
Synthesisers can be reprogrammed more easily than crystals
Synthesisers are cheaper to use
A frequency synthesiser in a radio requires 10kHz channel spacing. Which of these combinations would work
A 1MHZ crystal and a divide by 80 fixed divider
A 5MHz crystal and a divide by 500 fixed divider
A 500kHz crystal and a divide by 100 fixed divider