Archive for February, 2010

Visit to Itaipu Dam

As part of the LASCAS symposium, the organizers had planned a visit to Itaipu Dam. Built on the Paraná River, this massive hydroelectric power plant was a joint project between Brazil and Paraguay, with the purpose of serving the power needs of both countries. We got an extensive tour of the internals of the dam, including the production building, outflow channel and central command stations. The control room was quite fascinating, with live activity and monitoring as we filed in and out of the viewing rooms.

Most of the symposium participants took advantage of this opportunity, and made up quite a large tour-group. It took a while to reach the central control buildings as we had to pass through security gates and drive over part of the structure (the dam has a total length of 7.235 km). We walked through the gigantic structure and tried to imagine the size of each of the 20 turbines required to generate 14,000 MW. We were informed that the dam produces 90% of Paraguay’s electricity and 25% of Brazil’s. At peak production, a mind-boggling 62,200 cubic meters of water flows through the structure every second.

Rounding off the evening was short talk and light-show projected against the walls of the dam, as viewed from a not-too-distant amphitheater no doubt created for propaganda and other such events. The tour message was overwhelmingly favorable towards the project. In reality, the local communities paid a high price in order to accomodate the enormous size of the reservoir (29 billion cubic meters), including the displacement of over 10,000 families and the permanent destruction of Guaíra Falls (the worlds largest waterfall by volume) and the Guaíra Falls National Park, as well as the extinction of some rare plant types.

From an engineering perspective, I appreciated the sheer scale of the structure. As a human being, I felt sad for the loss and destruction. On the whole, the visit was quite an experience.

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This morning, I presented my paper titled An Architecture for First-Order Tunable Mismatch Shaping in Oversampled Data Converters at the 2010 IEEE Latin American Symposium on Circuits and Systems (LASCAS) taking place in Iguaçu Falls, Brazil. Coupled with the sister conference IBERCHIP, the organization and execution of this inaugural LASCAS symposium was impressed. The conference program can be found here (pdf). My paper was part of an interesting session on data converters (L2: Data Converters).

From the abstract:

Mismatch shaping is a commonly used technique for shaping the noise created by mismatch errors in over-sampled digital-to-analog converters. Mismatch shaping techniques reported thus far operate with the signal band located at a fixed frequency. This paper presents a simple architecture for arbitrarily tuning the center frequency of a first-order mismatch shaping transfer function. Details of hardware implementation are provided, and the hardware complexity is analyzed. Results from simulations show a consistently improved signal-to-noise ratio at tuning frequency settings across the entire Nyquist bandwidth.

Edit: A pre-publication version of the paper can be downloaded here (pdf).

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