Hardware circuit design of the latest sine wave os

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The hardware circuit design of the new sine wave oscillation source

the hardware circuit uses the oscillator chip ad2s99 as the sine wave generation source, the high-precision broadband operational amplifier lmll6702 is used to adjust the signal amplitude, and the output stage uses the current buffer chip lla5002 to drive the load

1 ad2s99

ad2s99 is a high-performance Programmable Sine wave oscillator produced by ad company, which is mainly used to provide high-quality sine wave excitation for resolvers and various AC converters. The ad2s99 standard output frequencies are 2 kllz, 5 kllz, 10 kllz and 20 kllz, which can be adjusted by setting the logic level of the reference analysis pin sel and sel2. In addition, the corresponding intermediate frequency can be obtained by adjusting the size of the connection resistance between the pin fbias and VDD. The root mean square value of the sine wave transmitted by ad2s99 is 2 V, the maximum root mean square value of the load current is 8 Ma, the frequency stability and amplitude stability can reach ± 5% and ± 3% respectively, and the total harmonic distortion is - 25 dB. In this paper, ad2s99 is used as the oscillation source to generate sine wave, and its peripheral circuit design is shown in Figure 1. Through jumper JPL ~ jp5 and adjusting resistance R; Ad2s99 can output sine wave signal of any frequency between 2 and 20 kllz. In order to meet the input voltage range of the later stage operational amplifier lmll6702, the output end of ad2s99 is divided by resistors R. and R, and then connected to the input end of lmll6702. In addition, due to the small output current of ad2s99 (root mean square 8 m to measure the stress change a on the sample), it cannot meet the requirements of large load driving, so a power driver needs to be added to the circuit output stage to increase the driving capacity

2 lmll6702

because the amplitude of the output sine wave of ad2s99 is fixed, in order to obtain a sine wave with adjustable amplitude to adapt to different systems, connect a primary operational amplifier lmll6702 at the output end of ad2s99, and adjust the amplitude of the sine wave by changing the gain of the operational amplifier. Lmll6702 is an ultra-low distortion, broadband operational amplifier, which is mainly used for high-speed A/D drive or D/a buffer. Its main performance parameters are shown in table L. Excessive noise and harmonic distortion. The condenser of lmll refrigeration system is regularly cleared 670291. The enclosure circuit design is shown in Figure 2. Adjusting the resistance R can change the amplitude of the output sine wave, R, with a value range of 318 N ~ 200 kn

3 lia-5002

iia-5002 is a high-voltage swing rate, large output current drive chip produced by American ntersil company, which is mainly used for broadband high-power current drive. The voltage swing rate of the chip is 1300 V/us, the maximum output current is ± 200 Ma, the 3 dB bandwidth is l0 mllz, and the harmonic distortion is less than 86db (v=1 V root mean square, f=10 kHz) Using iia-5002 as the current driver of the circuit output stage, the peripheral circuit design is simple, and the purpose of power drive can be achieved without affecting the performance of sine wave by filtering and decoupling the power and removing the residual source in the oil tank

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