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Single transistor emitter-follower circuit. The Butler oscillator is a crystal-controlled oscillator that uses the crystal near its series resonance point. They are used where a simple low-cost circuit is needed which can oscillate at high frequencies (>50MHz [1]) by using overtones of a crystal, and also giving low phase noise.
A blocking oscillator (sometimes called a pulse oscillator) is a simple configuration of discrete electronic components which can produce a free-running signal, requiring only a resistor, a transformer, and one amplifying element such as a transistor or vacuum tube.
An active-filter tuned oscillator is an active electronic circuit designed to produce a periodic signal. It consists of a bandpass filter and an active amplifier, such as an OP-AMP or a BJT. The oscillator is commonly tuned to a specific frequency by varying the reactant of the feedback path within the circuit. An example is the Colpitts ...
A basic Direct Digital Synthesizer consists of a frequency reference (often a crystal or SAW oscillator), a numerically controlled oscillator (NCO) and a digital-to-analog converter (DAC) [5] as shown in Figure 1. The reference oscillator provides a stable time base for the system and determines the frequency accuracy of the DDS.
Clock outputs are "pullable," i.e., their frequency can be "pulled" or fine-tuned. VCXO outputs can be pulled using an analog voltage input. TCXO – Temperature Compensated Oscillator and VC-TCXO – Voltage Controlled TCXO 0.5–5 ppm High-performance equipment that requires very stable frequencies: networking; base stations; femtocells ...
The voltage across C 2 is applied to the base-emitter junction of the transistor, as feedback to create oscillations. Fig. 2 shows the common-collector version. Here the voltage across C 1 provides feedback. The frequency of oscillation is approximately the resonant frequency of the LC circuit, which is the series combination of the two ...
[5] [6] Vackář was also concerned with the amplitude variations of the variable-frequency oscillator as it is tuned through its range. Ideally, an oscillator's loop gain will be unity according to the Barkhausen stability criterion. In practice, the loop gain is adjusted to be a little more than one to get the oscillation started; as the ...
Block diagram. The NE612 is an integrated circuit for processing of signals, such as in the transmission of radio signals. It consists of an oscillator and a mixer. [1] It can handle signal frequencies of up to 500 MHz and local oscillator frequencies of up to 200 MHz.