# How does an integrating receiver work?

I am reading some papers and in one paper, the working of an integrating receiver is mentioned to remove (periodic) interference from the received signal. The paper explains the working as such:

The integrating receiver utilizes the constant amplitude of the data signal and the periodic time-varying amplitude of the sinusoidal interference signal to separate them by integrating them over a fixed period of time. The constant amplitude data keeps on adding up as it is integrated over time. However, the periodic sinusoidal interference still remains a sinusoid even after integration. The periodic zero crossing of these sinusoids enables the possibility of sampling at appropriate instants to have zero integrated interference.

The I-DDR receiver utilizes the integration, followed by periodic sampling, on periodic interference affected constant amplitude nonreturn to zero (NRZ) data to achieve interferencerobust operation through signal interference separation in the time domain.

S. Maity, B. Chatterjee, G. Chang and S. Sen, "BodyWire: A 6.3-pJ/b 30-Mb/s −30-dB SIR-Tolerant Broadband Interference-Robust Human Body Communication Transceiver Using Time Domain Interference Rejection," in IEEE Journal of Solid-State Circuits, vol. 54, no. 10, pp. 2892-2906, Oct. 2019, doi: 10.1109/JSSC.2019.2932852.

Now I have the following questions:

1. You integrate the data signal, now you have the data signal added over a period of time. So? What can I do with that?
2. If we integrate the interference signal at its zero crossings, then we would have a integration value of ~zero over a period of time. So we have "nothing." How can we use that to separate the interference signal from the data signal?

I feel like I am missing the point of this integrating receiver a bit but maybe someone could explain it to me.

• Did you consider that linking the document you refer to was unimportant when asking this question? Commented Jan 5, 2023 at 10:39
• An integrator is just another way of saying 'low pass filter'. The text you've shown basically says they have added a low pass filter to the received data signal to remove a higher frequency interference signal. That's sig-pro 101 stuff. I don't know why they have chosen such a convoluted way of saying this, but I don't have access to the full paper to try to figure out the context better.
– Jon
Commented Jan 5, 2023 at 10:52
• You integrate the data signal, now you have the data signal added over a period of time. <-- not if you differentiate the data signal at the transmitter. It's called pre-emphasis (transmitter) and de-emphasis (receiver). Commonly used in FM broadcast. I'm not saying that it's done for the same reasons as the inaccessible (to me) paper but, it is a method used to improve SNR. Commented Jan 5, 2023 at 11:02
• One thing to note is that the interference is periodic, ie it's not noise, it's predictable. What they are doing is 'receiving' the signal and 'receiving' the interference, the better to separate them. This technique would not work if the interference was unpredictable noise. Commented Jan 5, 2023 at 12:13
• Maybe I missed it, but I looked at the entire paper you linked, and I didn't see the text you quoted anywhere in it. Commented Jan 5, 2023 at 17:01