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AD5933和AD5944区别

AD5933和AD5934的时钟频率差异的相关问题?

1.时钟频率相差4倍,AD采样频率是不是也相差4倍?

AD5933:1MSPS       AD5934:250kSPS

但是在AD5933的中文文档中AD采样速率和英文文档不符,如果是笔误,建议更正文档。

2.AD采样频率是否和    外部时钟频率在内部div分频后的频率   呈16.776/4倍数关系?还是说和内部时钟也有关?

3.AD5934是否能达到1k-100kHz频率输出范围?我注意到设置起始频率100kHz,起始频率寄存器还没有到0xFFFFFF。那么如果我设置起始频率500Hz或者120kHz,DDS能输出对应的频率吗,还是说输出其他频率?

4.虽然AD5933和AD5934文档中都说DDS输出频率分辨率都能达到0.1Hz,但我们只能通过频率增量寄存器设置DDS输出频率分辨率。那么当频率增量码最小为0x000001,AD5933和AD5934的输出频率分辨率是否相差4倍,不知道我理解的对不对。

Questions about clock frequency difference between AD5933 and AD5934?

1. The clock frequency differs by 4 times, and the AD sampling frequency also differs by 4 times?

AD5933: 1MSPS AD5934: 250kSPS

However, the AD sampling rate in the Chinese document of AD5933 does not match the English document. If it is a typo, it is recommended to correct the document.

2. Is the AD sampling frequency a 16.776/4 multiple of the external clock frequency divided by the internal div? Or is it also related to the internal clock?

3. Can the AD5934 achieve a frequency output range of 1k-100kHz? I noticed that setting the start frequency to 100kHz, the start frequency register has not reached 0xFFFFFF. So if I set the starting frequency to 500Hz or 120kHz, can DDS output the corresponding frequency, or other frequencies?

4. Although the AD5933 and AD5934 documents both say that the DDS output frequency resolution can reach 0.1Hz, we can only set the DDS output frequency resolution through the frequency increment register. Then when the minimum frequency increment code is 0x000001, whether the output frequency resolution of AD5933 and AD5934 is different by 4 times, I don't know why



English translation added.
[edited by: Antonius at 7:08 AM (GMT -4) on 20 Jun 2022]
  • Questions about clock frequency difference between AD5933 and AD5934?

    1. The clock frequency differs by 4 times, and the AD sampling frequency also differs by 4 times?

    AD5933: 1MSPS AD5934: 250kSPS

    However, the AD sampling rate in the Chinese document of AD5933 does not match the English document. If it is a typo, it is recommended to correct the document.

    2. Is the AD sampling frequency a 16.776/4 multiple of the external clock frequency divided by the internal div? Or is it also related to the internal clock?

    3. Can the AD5934 achieve a frequency output range of 1k-100kHz? I noticed that setting the start frequency to 100kHz, the start frequency register has not reached 0xFFFFFF. So if I set the starting frequency to 500Hz or 120kHz, can DDS output the corresponding frequency, or other frequencies?

    4. Although the AD5933 and AD5934 documents both say that the DDS output frequency resolution can reach 0.1Hz, we can only set the DDS output frequency resolution through the frequency increment register. Then when the minimum frequency increment code is 0x000001, whether the output frequency resolution of AD5933 and AD5934 is different by 4 times, I don't know why

  • 1. Yes, the sampling rate of the ADC is wrong in the chinese version of the datasheet.

    2. 16.776 MHz is the frequency of the internal oscillator of AD5933. The AD5934 does not have this feature. This oscillator can be used to reduce cost or board area but it is not as precise as a quartz-based clock. If an external oscillator is used, the recommended frequency is 16 MHz. Both the DAC and the ADC operate from the same clock source with different dividers.

    3. Both the AD5933 and AD5934 have a frequency output range from 1 kHz to 100 kHz. It is possible to configure a frequency outside this range but the part operates outside the specifications given in the datasheet.

    4. The frequency increment is 0.03 Hz for AD5934 and 0.008 Hz for AD5933. However the phase accumulator is truncated when addressing the look-up table of the DDS, resulting in a common limitation of 0.1 Hz resolution for both chips.