CN106324540A - Rapid measurement method for frequency response of digital oscilloscope and digital oscilloscope - Google Patents

Abstract

The application discloses a rapid measurement method for a frequency response of a digital oscilloscope. Only one external step signal is used as a testing signal; and a series of mathematical operations are carried out based on the powerful signal processing function of the digital oscilloscope; rapid measurement is carried out to obtain a frequency response results of the digital oscilloscope; and then the result is displayed on a display screen of the digital oscilloscope directly or is stored into the digital oscilloscope. The testing speed is fast, the method is simple and convenient and the efficient is high. In addition, the invention also discloses a corresponding digital oscilloscope.

Description

The method for fast measuring of a kind of digital oscilloscope frequency response and digital oscilloscope

Technical field

The application relates to digital oscilloscope, particularly relates to method for fast measuring and the number of a kind of digital oscilloscope frequency response Word oscillograph.

Background technology

The frequency response of digital oscilloscope is to weigh one of good and bad most important index of digital oscilloscope, mainly comprises band Width and inband flatness.Bandwidth directly determines the frequency range of the analogue signal that oscillograph is able to receive that, and in good band Flatness is to ensure that the important prerequisite of signal quality.The measuring method of traditional digital oscilloscope frequency response is frequency sweep method, i.e. By the digital oscilloscope described in a broadband swept signal generator connection, by constantly changing the defeated of swept signal generator Go out signal frequency, allow digital oscilloscope gather signal and to measure the reception amplitude data of respective frequencies point, then by computer or Manually test data are carried out Form Handle, thus draw out the frequency response curve of digital oscilloscope.But, such method Owing to measure respectively for multiple Frequency points so that measurement time-consuming the longest, and need to carry out frequency response curve Draw so that testing efficiency is relatively low；It addition, such method is higher to the requirement of test instrunment so that the hardware cost of test Higher, because more than band a width of MHz rank of existing main flow digital oscilloscope, high-end oscillographic bandwidth even reaches GHz rank, To test the digital oscilloscope of such high bandwidth, the swept signal generator of use must possess higher bandwidth, Yi Jigeng Good inband flatness.

Summary of the invention

In order to overcome the shortcoming that method is time-consumingly grown, testing efficiency is low of traditional measurement digital oscilloscope frequency response, this Shen A kind of method that can quickly measure the frequency response of digital oscilloscope own and digital oscilloscope please be provided.

According to the first aspect of the application, the application provides the method for fast measuring of a kind of digital oscilloscope frequency response, It is characterized in that, including:

Obtain outside step signal；

Step signal passes through channel of digital oscilloscope, obtains step response；

Step response is carried out derivation, obtains the impulse response of described channel of digital oscilloscope；

Impulse response is carried out fast Fourier transformation operation, obtains the frequency response knot of described digital oscilloscope itself Really.

Preferably, described step signal is produced by the driving source that arbitrarily can produce step signal.

Preferably, described method for fast measuring also includes the frequency response image of described digital oscilloscope measurement obtained It is directly displayed on the display screen of self of described digital oscilloscope.

Preferably, described method for fast measuring also includes the frequency response data of described digital oscilloscope measurement obtained It is stored in the memorizer of described digital oscilloscope self.

According to the another aspect of the application, the application provides a kind of digital oscilloscope, it is characterised in that including:

Oscillograph step response passage, is used for receiving step signal, generates step response；

Measurement module, for phase step response signals is carried out derivative operation and fast Fourier transform, obtains described numeral The frequency response results of oscillograph itself.

Preferably, described quick measurement module includes:

Derivative operation unit, for phase step response signals is carried out derivation, obtains the impulse of described channel of digital oscilloscope Response signal；

Fast Fourier transform unit, for impulse response signals is carried out fast Fourier transformation operation, obtains described The frequency response results of digital oscilloscope.

Preferably, described digital oscilloscope also includes display screen, the frequency of the described digital oscilloscope for measurement being obtained Rate response image is directly displayed on the display screen of self of described digital oscilloscope.

Preferably, described digital oscilloscope also includes memorizer, the frequency of the described digital oscilloscope for measurement being obtained Rate response data is stored in the memorizer of described digital oscilloscope self.

The application provides the benefit that:

Only need to receive an outside step signal as test signal, utilize the signal processing that digital oscilloscope itself is powerful Function, after carrying out a series of mathematical operation, just can directly obtain the frequency response of digital oscilloscope itself with quickly measuring.With existing Technology is had to compare, it is not necessary to connect digital oscilloscope by a broadband swept signal generator, decrease purchasing into of equipment This, it is not necessary to the amplitude of multiple frequencies is tested by constantly changing the output signal frequency of swept signal generator, it is not required that By computer or manually test data are carried out Form Handle again, draw the frequency response curve of digital oscilloscope, improve Test speed, method is simple, direct, convenient, in hgher efficiency.

Accompanying drawing explanation

Fig. 1 provides the flow chart of the method for fast measuring of a kind of digital oscilloscope frequency response for the embodiment of the present application；

Fig. 2 provides a kind of digital oscilloscope part-structure block diagram for the embodiment of the present application.

Detailed description of the invention

Combine accompanying drawing below by detailed description of the invention the application is described in further detail.

Embodiment one:

Refer to Fig. 1, the embodiment of the present application provides the method for fast measuring of a kind of digital oscilloscope frequency response, including with Lower step:

Step 10, obtains outside step signal.

Preferably, described step signal is produced by the driving source that arbitrarily can produce step signal.

Step 20, step signal obtains step response by channel of digital oscilloscope.

Step generator one unit step signal of output:

$u\left(t\right)=\left\{\begin{array}{cc}0,& t<0\\ 1,& t\&GreaterEqual;0\end{array}\right.$

Wherein, u (t) is step signal, and t is the time.

Theoretical according to Signals & Systems, the step that step signal is referred to as this system through the output that linear system obtains is rung Should, and channel of digital oscilloscope is linear system, step signal obtains step response after channel of digital oscilloscope, is denoted as s (t)。

The derivative of described unit step signal is unit impulse signal, i.e. u ' (t)=δ (t), and unit impulse signal δ (t) has Have:

$\left\{\begin{array}{c}{\&Integral;}_{0-}^{0+}\mathrm{\&delta;}\left(t\right)dt=1,\\ \mathrm{\&delta;}\left(t\right)=0,t\&NotEqual;0\end{array}\right..$

Step 30, carries out derivation to step response, obtains the impulse response of described channel of digital oscilloscope.

If the frequency response of a channel of digital oscilloscope is H (f), described frequency response is this channel of digital oscilloscope The Fourier transform of unit impulse response h (t), is denoted as:

Then, step response is equivalent to the convolution of step signal and impulse response, it may be assumed that

S (t)=u (t) * h (t)

According to the Differential Properties of convolution, to step response, then have,

S ' (t)=u ' (t) * h (t)

=δ (t) * h (t)

=h (t)

Thus obtain impulse response h (t) of described channel of digital oscilloscope.

Step 40, fast Fourier transform step.Impulse response is carried out fast Fourier transformation operation, obtains described number The oscillographic frequency response results of word.Frequency response results is directly displayed on the display screen of digital oscilloscope, or is archived in In digital oscilloscope.

Described fast Fourier transform (FFT) is important algorithm conventional in signal processing and data analysis field, for The fast algorithm of discrete Fourier transform (DFT), can make algorithm complex reduce, and carries out data operation quickly.In this enforcement In example, impulse response signals is carried out fast Fourier transformation operation, can comparatively fast obtain operation result, the oscillography of the most described numeral The frequency response of device.

The present embodiment only need to use an outside step signal as test signal, utilizes digital oscilloscope itself powerful Signal processing function, after carrying out the computing such as derivative operation and fast Fourier transform, just can directly obtain numeral with quickly measuring The frequency response of oscillograph itself, and frequency response is directly displayed on the display screen of digital oscilloscope, or it is archived in numeral In oscillograph, just can quickly measure the frequency response obtaining oscillograph itself.Compared with prior art, it is not necessary to wide by one Band swept signal generator connects digital oscilloscope, decreases the acquisition cost of equipment, it is not necessary to believe by constantly changing frequency sweep The output signal frequency of number generator tests the amplitude of multiple frequencies, it is not required that by computer or manually carry out test data Form Handle, draws the frequency response curve of digital oscilloscope, and method is simple, direct, convenient, in hgher efficiency.

Embodiment two:

Refer to Fig. 2, the embodiment of the present application provides a kind of oscillograph, including:

Channel oscilloscope, quick measurement module, display screen and memorizer, quick measurement module respectively with channel oscilloscope, Display screen is connected with memorizer, and other parts unrelated with frequency response test are not shown.

Described channel oscilloscope 11 is used for receiving step signal, generates step response；

Described quick measurement module 12, for step response is carried out derivative operation and fast Fourier transform, obtains described The frequency response of digital oscilloscope；

Described display screen 51, the frequency response image of the described digital oscilloscope for measurement being obtained is directly displayed at institute State on the display screen of self of digital oscilloscope；

Described memorizer 52, the frequency response data of the described digital oscilloscope for measurement being obtained is stored in described number In the memorizer of word oscillograph self.

Preferably, quick measurement module 12 includes:

Derivative operation unit 31, for step response is carried out derivation, the impulse obtaining described channel of digital oscilloscope rings Induction signal；

Fast Fourier transform unit 41, for impulse response signals is carried out fast Fourier transformation operation, obtains institute State the frequency response of digital oscilloscope.

The frequency response of itself can quickly be measured by the digital oscilloscope that the present embodiment provides.Specifically measure process For, step signal is by, after channel oscilloscope, obtaining step response, carry out phase step response signals in derivative operation and quick Fu After the computings such as leaf transformation, obtain the frequency response results of digital oscilloscope itself, frequency response results is directly displayed at numeral On oscillographic display screen, or it is archived in digital oscilloscope.

Only need to receive an outside step signal as test signal, utilize the signal processing that digital oscilloscope itself is powerful Function, after carrying out the computing such as derivative operation and fast Fourier transform, just can directly obtain digital oscilloscope originally with quickly measuring The frequency response of body, and frequency response is directly displayed on the display screen of digital oscilloscope, or be archived in digital oscilloscope. Compared with prior art, it is not necessary to a broadband swept signal generator connects digital oscilloscope, decreases purchasing of equipment Cost, it is not required that test the amplitude of multiple frequencies by constantly changing the output signal frequency of swept signal generator, the most not Need by computer or manually test data to be carried out Form Handle again, draw the frequency response curve of digital oscilloscope, side Method is simple, direct, convenient, in hgher efficiency.

Above content is to combine the further description that the application is made by specific embodiment, it is impossible to assert this Shen Being embodied as please is confined to these explanations.For the application person of an ordinary skill in the technical field, do not taking off On the premise of the present application is conceived, it is also possible to make some simple deduction or replace.

Claims (8)

1. the method for fast measuring of a digital oscilloscope frequency response, it is characterised in that including:

Obtain outside step signal；

Described step signal passes through channel of digital oscilloscope, obtains step response；

Step response is carried out derivation, obtains the impulse response of described channel of digital oscilloscope；

Impulse response is carried out fast Fourier transformation operation, obtains the frequency response results of described digital oscilloscope itself.

2. the method for claim 1, it is characterised in that described step signal is by the excitation that arbitrarily can produce step signal Source produces.

3. method for fast measuring as claimed in claim 1 or 2, it is characterised in that also include described numeral measurement obtained Oscillographic frequency response image is directly displayed on the display screen of self of described digital oscilloscope.

4. method for fast measuring as claimed in claim 1 or 2, it is characterised in that also include described numeral measurement obtained Oscillographic frequency response data is stored in the memorizer of described digital oscilloscope self.

5. a digital oscilloscope, it is characterised in that including:

Channel oscilloscope, is used for receiving step signal, generates step response；

Measurement module, for phase step response signals is carried out derivative operation and fast Fourier transform, obtains the oscillography of described numeral The frequency response of device itself.

6. digital oscilloscope as claimed in claim 5, it is characterised in that described quick measurement module includes:

Derivative operation unit, for step response is carried out derivation, obtains the impulse response of described channel of digital oscilloscope；

Fast Fourier transform unit, for impulse response is carried out fast Fourier transformation operation, obtains the oscillography of described numeral The frequency response results of device itself.

7. the digital oscilloscope as described in claim 5 or 6, it is characterised in that also include display screen, for obtain measurement The frequency response image of described digital oscilloscope is directly displayed on the display screen of self of described digital oscilloscope.

8. the digital oscilloscope as described in claim 5 or 6, it is characterised in that also include memorizer, for obtain measurement The frequency response data of described digital oscilloscope is stored in the memorizer of described digital oscilloscope self.