Selection of Oscillator:
While in the Selection of Oscillator for a particular application, the following particulars are to be considered.
Frequency Range: The oscillator selected for a particular application should be capable of supplying an output signal whose upper and lower frequency limits exceed those required by the application.
Power and/or Voltage Requirements: The selection of oscillator for a particular application should be capable of generating the pertinent quantity with a magnitude large enough to meet the requirement.
Accuracy and Dial Resolution: The accuracy of an oscillator specifies how closely the output frequency corresponds to the frequency indicated on the dial of the instrument. Dial resolution indicates to what percentage of the output frequency value the dial setting can be read.
Amplitude and Frequency Stability: The amplitude stability is a measure of an oscillator’s ability of maintaining a constant voltage amplitude with variations in the output signal frequency.
Frequency stability determines how closely the oscillator maintains a constant frequency over a given time period. Sometimes the frequency stability is included in the accuracy specifications of the oscillator.
Waveform Distortion: This quantity is a measure of how closely the output waveform of the oscillator resembles a pure sinusoidal signal. Sometimes the oscillator is employed as a source in a test used for measuring the tendency of a circuit to distort a sinusoidal signal. In such tests, the distortion caused by the oscillator should be much less than the anticipated distortion because of the circuit under test.
Output Impedance: The output impedance of an oscillator specifies the impedance value of the load which must be connected to it for maximum power transfer. It is very important that the output impedance of the oscillator be equal to the characteristic impedance of the system to which it is to be connected.