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Tag: EQ

Hardware – Equalization and Pre-emphasis

Hardware – Equalization and Pre-emphasis

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Before we look at equalization and pre-emphasis, we should examine some fundamentals of waves and signals. A perfect square wave is a really useful way of representing a waveform in the time-domain, but it’s not the only way of looking at the signal.The name ‘time-domain’ may be new but the view is familiar to us all, you have amplitude on the vertical axis and time you have time on the horizontal scale. Ideal square waves need infinite bandwidth The square wave…

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Hardware – Comparing 10G SFP+ with XFP

Hardware – Comparing 10G SFP+ with XFP

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In the last post I discussed clock and data recovery (CDR). This post examines an application of re-timers (or CDRs) within XFP and SFP+ transceivers. I’ve previously covered the size, power and connector differences of 10G transceivers before, but this post will focus on the differences between XFP and SFP+ and how they connect to the ASIC. Take a look at the XFP block digram below which shows the XFI electrical interface from an XFP module connecting to the the host device (ASIC…

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Hardware – Clock and Data Recovery

Hardware – Clock and Data Recovery

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Clock and data recovery is an essential physical-layer function of modern switch and router hardware. Digging deep into the electronics of a router may not be your thing, but clock recovery is a fundamental building block for other network hardware functions. For example, serial to parallel data conversions require reliable clock and data recovery (CDR) to function effectively. It’s hard to understand serial to parallel conversions or signal conditioning without learning about CDR first.