Double-DA synchronous sampling device

Abstract

The invention discloses a double-DA synchronous sampling device which comprises a clock generate unit, a first DA sampling unit, a second DA sampling unit, an XOR unit, a phase-lock unit and a DA reset unit. According to the invention, clock signals are generated according to externally input frequency control words and are respectively adopted as sampling clocks of two DAs, four frequency division clocks respectively output by the two DAs are subjected to XOR treatment, then, signals output through XOR are input into a phase-lock loop, a phase-lock index signal is generated through the phase-lock loop, finally, the phase-lock index signal is sent into the DA reset unit, the DA reset unit performs judgment after the wobble elimination of the input phase-lock index signal wobble elimination is completed, and the two DAs are respectively reset if the result indicates that the two DAs are not synchronous in operation. According to the invention, from the aspect of XOR output signal duty ratio, the interference of peripheral circuits to extraction of synchronous signals is reduced, and the accuracy and reliability of operation of the double-DA synchronous sampling device are improved.

Description

technical field [0001] The invention relates to a double DA synchronous sampling device in the field of communication, and is especially suitable for generating quadrature modulation baseband signals in communication systems. Background technique [0002] With the improvement of communication system service rate and code rate, the current single DA digital up-conversion to achieve direct modulation will be limited by the sampling rate of the DA chip. In order to further increase the amount of transmitted data, a dual DA synchronous sampling device is used to generate quadrature modulation baseband signals. , and then the method of generating modulated intermediate frequency signals through IQ mixing will become more and more important. The most important thing when using dual DAs is to ensure that the two DAs can work synchronously at different sampling rates. The previous synchronization method uses a voltage comparator to determine Whether the DA works synchronously or not...

AI Technical Summary

Problems solved by technology

[0002] With the improvement of communication system service rate and code rate, the current single DA digital up-conversion to achieve direct modulation will be limited by the sampling rate of the DA chip. In order to further increase the amount of transmitted data, a dual DA synchronous sampling device is used to generate quadrature modulation baseband signals. , and then the method of generating modulated intermediate frequency signals through IQ mixing will become more and more important. The most important thing when using dual DAs is to ensure that the two DAs can work synchronously at different sampling rates. The previous synchronization method uses a voltage comparator to determine Whether the DA works synchronously or not, because the voltage signal is susceptible to external noise interference, which reduces its reliability. At the same time, because the voltage threshold values ​​​​of different applications are often inconsistent, it makes it more difficult to set the voltage comparator to compare the reference voltage, resulting in dual DA synchronous sampling. The device should not be debugged

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