Search results
Results from the WOW.Com Content Network
A digitally controlled oscillator or DCO is used in synthesizers, microcontrollers, and software-defined radios. The name is analogous with " voltage-controlled oscillator ". DCOs were designed to overcome the tuning stability limitations of early VCO designs.
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.
VCOs can be generally categorized into two groups based on the type of waveform produced. [4]Linear or harmonic oscillators generate a sinusoidal waveform. Harmonic oscillators in electronics usually consist of a resonator with an amplifier that replaces the resonator losses (to prevent the amplitude from decaying) and isolates the resonator from the output (so the load does not affect the ...
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 ...
Hartley oscillator using a common-drain n-channel JFET instead of a tube.. The Hartley oscillator is distinguished by a tank circuit consisting of two series-connected coils (or, often, a tapped coil) in parallel with a capacitor, with an amplifier between the relatively high impedance across the entire LC tank and the relatively low voltage/high current point between the coils.
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 numerically controlled oscillator (NCO) is a digital signal generator which creates a synchronous (i.e., clocked), discrete-time, discrete-valued representation of a waveform, usually sinusoidal. [1] NCOs are often used in conjunction with a digital-to-analog converter (DAC) at the output to create a direct digital synthesizer (DDS). [3]
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 ...