#CRYSTAL FILTER DESIGN FOR AM OPERATION SERIES#

There are various applications for crystal oscillator in various fields and some of the crystal oscillator applications are given belowД¬olpitts Oscillator is used to generate a sinusoidal output signal at very high frequencies.

This particular crystal oscillator which is having cycle rate at 1MHz to 3.33MHz is used to generate clock pulses that are required for the synchronization of all the internal operations. For instance, let us consider 8051 microcontrollers, in this particular controller an external crystal oscillator circuit will work with 12MHz that is essential, even though this 8051 microcontroller (based on model) is capable to work at 40 MHz (max) have to provide 12MHz in most of the cases because for a machine cycle 8051 requires 12 clock cycles, so that to give effective cycle rate at 1MHz (taking 12MHz clock) to 3.33MHz (taking the maximum 40MHz clock). In general, we know that, in the design of microprocessors and microcontrollers, crystal oscillators are used for the sake of providing the clock signals. The above diagram describes an equivalent circuit, plot graph for Resonant frequency, Formulae for Resonant frequencies.

#CRYSTAL FILTER DESIGN FOR AM OPERATION SERIES#

The fr and fp represents series and parallel resonant frequencies respectively, and the values of вЂfrвЂ™ and вЂfpвЂ™ can be determined by using the following equations shown in the figure below. The series resonance occurs when the reactance produced by capacitance C1is equal and opposite to the reactance produced by inductance L. The basic components used in the circuit, inductance L represents crystal mass, capacitance C2 represents compliance, and C1 is used to represent the capacitance that is formed because of crystalвЂ™s mechanical moulding, resistance R represents the crystalвЂ™s internal structure friction, The quartz crystal oscillator circuit diagram consists of two resonances such as series and parallel resonance, i.e., two resonant frequencies.

Just look at the equivalent electrical circuit diagram shown in the above. The equivalent electrical circuit also describes the crystal action of the crystal. Generally in Microprocessors and Micro controllers we are using an 8MHz crystal oscillator. Hence, quartz crystal oscillator circuits are more superior compared to other resonators like LC circuits, tuning forks. Usually, quartz crystal oscillators are highly stable, consist of good quality factor(Q), they are small in size, and are economically related. Thus, it utilizes the vibrating crystalвЂ™s mechanical resonance, which is made with a piezoelectric material for generating an electrical signal of a particular frequency. The applied electric field will produce a mechanical deformation across some materials. The crystal oscillator circuit usually works on the principle of the inverse piezoelectric effect.

The below figure represents the electronic symbol of a piezoelectric crystal resonator and also quartz crystal in an electronic oscillator that consists of resistor, inductor, and capacitors.Д¬rystal Oscillator Circuit Diagram Crystal Oscillator Working The distorted amount will be proportional to the applied voltage and also an alternate voltage applied to a crystal it causes to vibrate at its natural frequency. That voltage causes distortion in the crystal.

When mechanical pressure is applied across the faces of the crystal, a voltage which is proportional to mechanical pressure appears across the crystal. What is a Quartz Crystal?ДЄ quartz crystal exhibits a very important property known as the piezoelectric effect. Soon we are going to discuss in detail crystal oscillators like working and applications of a crystal oscillator. Relaxation oscillators вЂ“ Royer oscillator, Ring oscillator, Multivibrator and Voltage Controlled Oscillator (VCO). There are different types of oscillator electronic circuits that are in use they are namely: Linear oscillators вЂ“ Hartley oscillator, Phase-shift oscillator, Armstrong oscillator, Clapp oscillator, Colpitts oscillator.

Crystal filter design for am operation