hi, i am developing a weigh scale application using Cirrus Logic 5532 24-bit ADC in unipolar mode.the output i am getting is very unstable (flickering on display). Can anybody please tell me how to get a stable count.
Mine is a small budget project so i cannot invest in a DSP plus i have no prior experience in DSPs. You don't need a DSP chip to do digital signal processing. The moving average filter is not computationally demanding because it is easy to maintain the sum of all the values in a buffer. When a new value is added to the buffer, its value is also added to the sum. When an old value is released from the buffer its value is subtracted from the sum. It does not matter how long your buffer is, you just do one add and one subtract for each new value. An 8051 should be able to do this easily, all you will need is sufficient memory to store the buffer. Of course, for all the reasons already mentioned, DSP is not the answer to all problems with noise. However, it is likely that a moving average filter will find a proper place somewhere in your application.
We use the same CS5532 for current measurement in battery management systems and I agree that its output might be very noisy. I use the upper 16 bits of the 24 bit AD-result and there's still noise. Noise depends on the hardware design (PCB Layout...). Don't use the same ground and supply for AD-converter and controller. The controller is very noisy, and that might also influence its supply. Before using software filtering (moving AVG), a hardware filter (i.e. anti aliasing filter) and perhaps a pre-amplifier (instrumention amplifier) is necessary.