5.4.1 The basic composition and principle of a function signal generator.
1.Pulsed function signal generators.
The block diagram of the pulsed function signal generator is shown in Figure 514.
Figure 515 shows a typical diode network conversion circuit that converts a symmetrical triangular wave into a sine wave.
2.Sinusoidal function signal generator.
The block diagram of the sinusoidal function signal generator is shown in Figure 516.
3.Trigonometric wave function generator.
The block diagram of the triangular wave function signal generator is shown in Figure 517.
5.4.2 Key performance indicators of the function signal generator.
For function signal generators, the performance indicators are:
1) Output waveform: Usually the output waveform has sine wave, square wave, pulse and triangle wave, and some also have sawtooth wave, oblique wave, TTL synchronous output and single pulse output.
2) Frequency range: The entire working frequency range of the function generator is generally divided into several frequency bands, such as 1 10Hz, 10 100Hz, 100Hz 1khz, 1 10kHz, 10 100khz, 100kh 1MHz and other bands.
3) Output voltage: For sinusoidal signals, it generally refers to the peak-to-peak value of the output voltage, which can usually reach more than 10up-p; For pulsed digital signals, TTL and CMOS output levels are included.
4) Waveform characteristics: Different waveforms have different representations. The characteristics of the sine wave are generally expressed by the nonlinear distortion coefficient, which is generally required to be less than or equal to 3%; The characteristics of triangular waves are expressed by nonlinear coefficients, which are generally required to be less than or equal to 2%; The characteristic parameter of the square wave is the rise time, which is generally required to be less than or equal to 100 ns.
5) Output impedance: function output 50; TTL synchronous output 600.