Variable Frequency Sine Wave Oscillator

The state variable filter based oscillator shown above is also known as a quadrature oscillator because it produces two sinewaves in quadrature they are exactly 90 apart sine and cosine.

Variable frequency sine wave oscillator.

Variable frequency sine wave oscillator 2 sheets sheet 1 may 7 1968 filed feb. Y 7 1968 m. Sine wave oscillators are used as references or test waveforms by many circuits. Considering the size of most ham bands a vfo needs a tuning range of at least 0 5 mhz.

A variable frequency oscillator vfo in electronics is an oscillator whose frequency can be tuned i e varied over some range. A one transistor fet hartley oscillator is hard to beat for cheap. The resonant point of the network. Make offer kenwood vfo 820 remote variable frequency oscillator.

It is a necessary component in any tunable radio receiver or transmitter that works by the superheterodyne principle and controls the frequency to which the apparatus is tuned. By the way if you need a crystal oscillator with a sine wave out you can usually buy a commercial circuit. Kenwood vfo 820 remote variable frequency oscillator. 2 1967 2 sheets sheet 2 lagging current phase angle phase angle tuned o circuit iurrent leading phase angle fig.

Isotemp 143 141 10mhz ocxo 5vdc. Its useful frequency range is approximately 100 khz to 40 mhz. 2pcs cts 1960017 10mhz 5v sine wave ocxo crystal oscillator. Also the very high input impedance levels and very low output impedance levels of the operational amplifier mean that there is minimal loading on.

Frequency conversion is covered in chapter 11. You didn t specify the frequency 100hz or 100mhz or how much the frequency had to be varied 0 01 or 1000 or whether the frequency had to be varied by a voltage or a physical knob. A pure sine wave has only a single or fundamental frequency ideally no harmonics are present. Hp hewlett packard 201 audio oscillator 115 130 volt.

Oscillators may produce a single sine wave with a carefully controlled frequency or may output a range of frequencies by having multiple frequency controlling elements such as rc filters selected by a series of switches or keys and have their waveshape manipulated by extra circuitry for use in such systems as electronic keyboards. One sinewave is available from u2a as shown technically this is the cosine delayed by 90 with respect to the sine output and another can be taken. For the eelctronic circuit design of a sine wave oscillator the bridge can be used within the feedback loop and the circuit oscillates at the balance point i e. Purity of sine wave and stability matters too.

The higher the basic frequency of the vfo the wider the tuning range you can achieve. This is done by adding the vfo to a high frequency crystal oscillator signal and then filtering out the sum frequency. This is another widely used circuit because it s easy to implement and very stable. Thus a sine wave may be the input to a device or circuit with the output harmonics measured to determine the amount of distortion.