Working principle and type selection of signal generator

Signal generator is also called signal source , It can be widely used in practical production practice and scientific research . The signal generator can be used to generate various waveforms , In the test 、 When studying or adjusting electronic circuits and equipment , It can be used to measure some electrical parameters of the circuit , Such as measuring frequency response 、 Noise factor 、 Voltmeter calibration and other important parameters . It is required to provide electrical signals that meet the technical premise , Simulate the excitation signal of the equipment to be tested used in the actual work . When measuring the steady-state characteristics of the system , A sinusoidal signal source of known amplitude and frequency shall be used . When testing the transient characteristics of the system , The known leading edge time must be used 、 Rectangular pulse source with pulse width and repetition period . The frequency of the output signal of the signal source 、 wave form 、 The output voltage or power and other parameters shall be accurately adjusted within a certain range , It has good non disorder and output indication .

Division of signal sources

If the signal generator is divided into signal sources , It can be roughly divided into mixed signal source and logic signal source . But the mixed signal source mainly outputs analog waveform ; The logic signal source outputs a digital code shape . Mixed signal source can be divided into function signal generator and arbitrary waveform / Function generator , The function signal generator outputs the standard waveform , Like a sine wave 、 Fang Bo, etc , Arbitrary wave / The function generator outputs any waveform set by the user ; For example, Xi'an synchronous Electronics Co., Ltd SYN5651 Type signal generator . It is a product that can meet 《JJG 173-2003 Verification regulation of signal generator 》 and 《JJG 502-2017 Verification regulation of synthetic signal generator 》 Economical electronic measuring instrument .

The signal generator adopts high-tech digital synthesis and phase-locked technology , The output frequency can reach up to 6GHz, Rich modulation functions , Widely used in communications 、 metering 、 In national defense and scientific experiments , It is very suitable for teaching and experiment in Colleges and universities .

in addition , The signal source can also be classified according to the type of output signal , Such as radio frequency Signal generator 、 Scanning signal generator 、 frequency synthesis device 、 Noise signal generator 、 Pulse generator, etc . Signal sources can also be classified according to the frequency band used , Signal sources of different frequency bands correspond to different application fields .

The pulse signal generator is mainly used to provide pulse signals for testing the dynamic characteristics of pulse circuits and digital circuits . Such as studying the limiting characteristics of the limiter 、 Clamping characteristics of clamping circuit 、 Trigger characteristics of trigger 、 Switching characteristics and delay time of gate circuit 、 Switching speed of switching circuit and digital integrated circuit and computer circuit , Pulse signals are required .

Selection considerations ：

Sine wave ：

Sine wave is the single frequency component The signal , Because of this signal wave form It's mathematical Sine curve And get the name . Any complex signal —— For example, music signal , Can be seen by many different frequencies 、 Sine waves of different sizes are compounded .SYN5651 Type signal generator Sine wave measurement range ：5μHz～350MHz.

square wave ：

Square wave is a kind of non Sine curve Waveform of , Usually associated with electronics and signal processing . The ideal square wave has only “ high ” and “ low ” These two values . A signal with a rectangular waveform of current or voltage is Rectangular wave The signal , The time ratio occupied by the high level in a waveform period is called Duty cycle , It can also be understood as the ratio of the effective release time of the circuit to the total release time ,SYN5651 Measurement range of sine wave of signal generator ：5μHz～80MHz.

The resolution of the ：

If the input of an instrument changes slowly from any non-zero value （ Increase or decrease ）, Enter the change value Δ Before a certain value is exceeded , The indicated value of this instrument will not change , But when you enter a change value Δ Beyond a certain value , The indicated value of the instrument changes . The minimum input change that changes the indicated value is called the resolution of the instrument .SYN5651 The resolution of the signal generator ：5μHz （ Carrier frequency ≤80MHz）;1Hz（ Carrier frequency >80MHz）.

Accuracy ：

It refers to many times under certain experimental conditions Determination Of Average And Truth value The degree of conformity , It is used to indicate the magnitude of the error .SYN5651 The accuracy of the signal generator ：±1ppm（ frequency ≥1.0kHz ）;±50ppm（ frequency ＜1.0kHz）.

Internal Timebase ：

Standard equipment ： Thermostatic crystal oscillator is called thermostatic crystal oscillator for short , The English abbreviation is OCXO, A constant temperature bath is used to make the crystal oscillator Quartz crystal resonator The temperature remains constant , The oscillator output frequency variation caused by ambient temperature change is reduced to a minimum Crystal oscillator . Accuracy （ Factory settings ）≤1E-8, Daily aging rate ≤5E-10, Annual aging rate ≤5E-8, Second stability ≤1E-11.

Conclusion

High precision signal generator can also be used as standard signal source in the field of measurement and calibration / Reference source , The instrument to be calibrated shall be calibrated with the reference source as the standard . Signal generator can be widely used in electronic research and development 、 maintenance 、 measurement 、 Calibration and other fields .