Sigma Delta Modulator for Low Power Application

Sigma-Delta modulation has become a popular means of converting narrow-band signals to digital ones. In recent times, there has been a growing emphasis on using sigma delta modulators in low power designs. However, most sigma delta ADC's operate with an oversampling ratio that is too high for broadband applications. Hence, designing a low power sigma delta modulator is the focus of this paper.

The best part about oversampling is that it does not require the same degree of circuit optimization as the Nyquist rate A/D converters. This is due to the fact that oversampling does not have the same sensitivity to circuit imperfections. Therefore, a sigma delta modulator is well suited for standard low cost CMOS technologies.

In this study, a DT-induced mouse model was tested for its ability to induce cardiac gene expression. To this end, a pirfenidone-treated DT-injured mouse was used. As expected, the transcriptional profile of the heart was altered in this model. Moreover, the presence of the mRNA in all biological replicates in any of six experimental groups was enough to make the cut.

Another intriguing component of the DT-induced mouse model was the ability to stimulate an apoptotic cascade. This was tested by chemiluminescent microparticle assay. Millipore S7200 ApopTag Peroxidase In Situ Oligo Ligation Apoptosis Detection's trichrome was used. Several parameters were measured, including the presence of TUNEL, troponin, and a cell cycle arrest index.

Using a hybrid CT/DT sigma-delta modulator, the same functionality can be realised with a low power budget.