On certain function generators the frequency control combines several different controls: one set of controls sets the frequency range, or order of magnitude, while the other selects the exact frequency.
This enables the function generator to handle the dramatic variation in frequency scale required for signals. You use a function generator by powering it on and configuring the output signal to your intended shape.
This entails connecting the ground and signal leads to your oscilloscope to check the controls. The main purpose of a function generator is to send a signal into a circuit for testing purposes. A technician will then observe the signal at various points in the circuit using an oscilloscope, spectrum analyzer, or some other type of testing equipment. The technician will know what is happening in the circuit if the signal is attenuated, distorted, or altogether absent.
In addition, one can also test systems of equipment by injecting a pure signal into a radio transmitter. Analyzing returned signals will reveal a great deal about transmission quality as well as reception quality. Also they are generally not used for performance audio testing as the levels of distortion on the sine aves that would normally be used would have higher levels of distortion than these tests sometimes require.
If very high frequency stability is required, ten some of these test instruments allow for the output signal to be phase locked to another source. There are several forms that the function generator can take. With modern digital technology there are many formats for this type of test equipment. Function generators are normally very easy to operate. With modern processing technology often included this gives the possibility of many additional features including ease of operation, and remote control via one or more of the many standards available.
A good variety of function generators are available for a number of different manufacturers and also via a number of different distributors. Costs are usually quite reasonable as they are normally quite straightforward and do not require very high frequency components. These test instruments can be either analogue or digital. Analogue ones tend to use operational amplifiers as the basis of the design, but digital ones can use some form of direct digital synthesis.
Function generator capabilities Function generators are capable of producing a variety of repetitive waveforms, generally from the list below: Sine wave: A function generator will normally be able to act as a sine wave generator. This is the standard waveform that oscillates between two levels with a standard sinusoidal shape. Using the function generator as a sine wave generator is one of the more commonly used applications.
Sine waves are widely used in testing applications. Square wave: Another very widely used waveform is the square wave. It consists of a signal moving directly between high and low levels. Many function generators are also capable of generating two different waveforms simultaneously from different output terminals, of course.
This can be a useful feature when two generated signals are required for a particular application. For another example, a triangular-wave and a sine-wave of equal frequencies can be produced simultaneously. If the zero crossings of both the waves are made to occur at the same time, a linearly varying waveform is available which can be started at the point of zero phase of a sine-wave. Another important feature of some function generators is their capability of phase-locking to an external signal source.
One function generator may be used to phase lock a second function generator, and the two output signals can be displaced in phase by an adjustable amount. In addition, one function generator may be phase locked to a harmonic of the sine-wave of another function generator. By adjustment of the phase and the amplitude of the harmonics, almost any waveform may be produced by the summation of the fundamental frequency generated by one function generator and the harmonic generated by the other function generator.
The block diagram of a function generator is given in the figure. In this instrument, the frequency is controlled by varying the magnitude of the current that drives the integrator. This instrument provides different types of waveforms such as sinusoidal, triangular and square waves as its output signal with a frequency range of 0.
The frequency controlled voltage regulates two current supply sources.
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