内部衰减器踩踏输出无法使用

声明“幅度分辨率：10位”表示在任意波形发生器中使用的DAC是10位DAC。
“由于内部衰减器步进而在输出端无法获得全分辨率”这一说法是警告用户，如果函数发生器发出的信号不是使用整个DAC范围产生的，则分辨率不会是10位。
考虑以下。
假设DAC输出，输出放大器增益和函数发生器的衰减器是这样的，为了提供10Vp-p输出，整个DAC范围使用0dB衰减。
在这种情况下，10Vp-p信号将具有10位分辨率。
现在让我们将输出幅度更改为9Vp-p。
为了产生这个9Vp-p信号，电路必须将DAC输出衰减0.9倍。
如果没有这样的衰减器，则唯一的选择是对DAC进行编程，以输出小于0.9的信号。
该信号不会使用DAC的满量程范围，因此不具有10位分辨率。
事实上，函数发生器中可用的衰减器步骤有限，这意味着DAC输出必须经常缩放，并且函数发生器信号不能总是具有10位分辨率。



     以下为原文

  The statement “Amplitude Resolution: 10 bits “, indicates the DAC used in the arbitrary waveform generator is a 10bit DAC.
The statement “Full resolution is not available at output due to internal attenuator stepping “, is to warn users that if the signal coming out of the function generator was not generated using the full range of the DAC, the resolution will not be 10bits.

Consider the following. Let us say the DAC output, output amplifier gain and attenuators of the function generator are such that in order to provide a 10Vp-p output, the full DAC range is used with 0dB of attenuation. In this case, the 10Vp-p signal would have 10bits of resolution. Now let us change the output amplitude to 9Vp-p. To generate this 9Vp-p signal, the circuit must attenuate the DAC output by a factor of 0.9. If no such attenuator is available, then the only option is to program the DAC to output a signal smaller by a factor of 0.9. This signal will not be using the full scale range of the DAC and, thus, not have 10bits of resolution.  The fact that there are limited attenuator steps available in the function generator means the DAC output must often be scaled and the function generator signal cannot always have 10bits of resolution.

嗨，Fungible：你说的是有意义的，也同意我目前正在进行的实验。
谢谢！
现在，只是为了好奇，我想知道是否有一种方法可以预测，给定所需的幅度和下载的任意波形的值，将产生什么样的分辨率。
而且，更重要的是，预期的最坏情况解决方案是什么。
你觉得这有可能吗？
Franco Web：http：//www.flanguasco.org



     以下为原文

  Hi, Fungible:
what you says makes sense of it and also agrees with the experiments that I am currently running.
Thank you!

Now, just for the sake of curiosity, I wonder if there is a way to predict, given the requested amplitude and the values of the downloaded arbitrary waveform, what is going to be the resulting resolution.
And, even more important, what is the expected worst case resolution.

Do you think this is possible?

Franco

Web: http://www.flanguasco.org

嗨，Fungible：你说的是有意义的，也同意我目前正在进行的实验。
谢谢！
现在，只是为了好奇，我想知道是否有一种方法可以预测，给定所需的幅度和下载的任意波形的值，将产生什么样的分辨率。
而且，更重要的是，最糟糕的情况解决方案是什么。
你觉得这有可能吗？
Franco Web：http：//www.flanguasco.org



     以下为原文

  Hi, Fungible:
what you says makes sense of it and also agrees with the experiments that I am currently running.
Thank you!

Now, just for the sake of curiosity, I wonder if there is a way to predict, given the requested amplitude and the values of the downloaded arbitrary waveform, what is going to be the resulting resolution.
And, even more important, what is the worst case resolution.

Do you think this is possible?

Franco

Web: http://www.flanguasco.org

你究竟想做什么，你是否担心决议？
这是一种低成本的信号发生器。
还有更多的错误来源会导致您比步骤解决更麻烦。
幅度精度为+/- 2％，仅在1KHz时指定。
DC模式下的DC精度为+/- 1.5％+ / - 3mV。
也就是说，大多数示波器衰减器使用1-2-5步进。
不能保证这里使用的是什么，但如果是，那么最坏的情况可能是最佳情况的2.5倍。
请注意，即使您知道步长，也无法明确知道DAC切换衰减的位置。
我通过考虑具体案例获得了2.5倍的数字。
例如，如果你假设DAC使用全范围来获得200mV，你想要201 mV，那么它将切换到下一个范围500mV，并使用40.2％的DAC范围来获得201 mV（非常接近）
。
免责声明：为了获得更可靠的响应，您应该考虑致电当地的安捷伦技术呼叫中心。
安捷伦论坛在“可用”的基础上进行监控，并不一定是解决技术问题的最快方式。



     以下为原文

  Exactly what are your trying to do, that you are that concerned about the resolution?

This is a low-cost signal generator. There are many more sources of error that will cause you more trouble than the step resolution. The amplitude accuracy is +/- 2%, and only specified at 1KHz. The DC accuracy in DC mode is +/- 1.5% +/- 3mV.

That said, most scope attenuators use 1-2-5 stepping. There is no guarantee that's what's being used here, but if it is, then the worst case could be as much as 2.5x the best case. Note that there is no way to know, definitively, where the DAC switches attenuation, even if you know the step size.

I got the 2.5X number by considering a specific case. If you assume, for instance, that the DAC uses full range to get 200mV, and you want 201 mV, then it will switch to the next range, 500mV, and use 40.2% of the DAC range to get 201 mV (very approximately).

Al

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