A35 - Oscillators

the drawing shows a typical Colpitts Oscillator. What is the function of R1 and R2?
1. To set the bias of the transistor
2. To control the frequency of the oscillator
3. To provide feedback and thus control the frequency of oscillation
4. To control the emitter current.
In the drawing of an oscillator, what would happen to the frequency if the value of L1 was increased?
1. Frequency would double
2. Frequency would stay the same
3. Frequency would decrease
4. Frequency would increase
In a frequency synthesiser the frequency step is determined by:
1. The programmable divider and the phase detector
2. Reference oscillator and fixed divider
3. Reference oscillator and the voltage controlled oscillator
4. The loop filter and the programmable divider
In a direct digital synthesiser the frequency is controlled by:
1. A programmable divider
2. Tables of binary numbers that are converted to a sine wave.
3. An analogue to digital converter
4. A phase accumulator
Calculate the output frequency from a phased lock loop type synthesiser. The crystal frequency is 1MHz, the programmable divider is set to 1000, the programmable divider is set to 5000.
1. 1MHz
2. 25MHz
3. 50MHz
4. 100MHz