A sweep generator is a piece of

electronic test equipment Electronic test equipment is used to create signals and capture responses from electronic devices under test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced. Use of electronic test equipmen ...

similar to, and sometimes included on, a

function generator In electrical engineering, a function generator is usually a piece of electronic test equipment or software used to generate different types of electrical waveforms over a wide range of frequencies. Some of the most common waveforms produced b ...

which creates an electrical

waveform In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time.David Crecraft, David Gorham, ''Electronic ...

with a linearly varying

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

and a constant

amplitude The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplit ...

. Sweep generators are commonly used to test the

frequency response In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of sy ...

electronic filter Electronic filters are a type of signal processing filter in the form of electrical circuits. This article covers those filters consisting of lumped electronic components, as opposed to distributed-element filters. That is, using components ...

circuits. These circuits are mostly

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...

circuits with

inductor An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a c ...

s and

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...

s to create linear characteristics. Sweeps are a popular method in the field of audio measurementLet's Clear Up Some Things About Sweeps
/ref> to describe the change in a measured output value over a progressing input parameter. The most commonly-used progressive input parameter is frequency varied over the standard audio bandwidth of 20 Hz to 20 kHz.

Glide Sweep

A glide sweep (or chirp) is a continuous signal in which the frequency increases or decreases logarithmically with time. This provides the complete range of testing frequencies between the start and stop frequency. An advantage over the stepped sweep is that the signal duration can be reduced by the user without any loss of frequency resolution in the results. This allows for rapid testing. Although the theory behind the glide sweep has been known for several decades, its use in audio measuring devices has only evolved over the past several years. The reason for this lies with the high computing power required.

Stepped Sweep

In a stepped sweep, one variable input parameter (frequency or amplitude) is incremented or decremented in discrete steps. After each change, the analyzer waits until a stable reading is detected before switching to the next step. The scaling of the steps is linear or logarithmic. Since the settling time of different test objects cannot be predicted, the duration of a stepped sweep cannot be determined exactly in advance. For the determination of amplitude or frequency response, the stepped sweep has been largely replaced by the glide sweep. The main application for the stepped sweep is to measure the linearity of systems. Here, the frequency of the test signal is kept constant while the amplitude is varied. Typically the amplitude and distortion of the device under test are measured. This is also referred to as an "amplitude sweep".

Time Sweep

In the case of a time sweep, the x-axis represents time. Again the y-axis represents a measured value, e.g. amplitude. The change in the measured value is observed over time. For example, how does the response of the device under test change over a long period?

Table Sweep

A rarely used special form of the stepped sweep is the table sweep. Here the input signal is produced from a table as a sequence of any frequency and amplitude pairs.

References

Electrical circuits {{electronics-stub

Glide Sweep

Stepped Sweep

Time Sweep

Table Sweep

See also

References