Delta Sigma Theta

Delta Sigma Theta (ΔΣΘ) is a not-for profit Greek-lettered sorority of college-educated women dedicated to public service with an emphasis on programs that target the African American community. Delta Sigma Theta Sorority was founded on January 13, 1913, by 22 collegiate women at Howard University. These students wanted to use their collective strength to promote academic excellence and to provide assistance to persons in need. The first public act of Delta Sigma Theta was the Women's Suffrage March in Washington D.C., March 3, 1913. Today, Delta Sigma Theta Sorority is the largest African-American Greek-lettered organization. Membership in Delta Sigma Theta is open to any woman who meets the membership requirements, regardless of religion, race, or nationality. Women may join through undergraduate chapters at a college or university, or after acquiring a college degree through an alumnae chapter.

Since its founding, Delta Sigma Theta has been at the forefront of creating programming to improve political, education, and social and economic conditions. Delta Sigma Theta has been pivotal in assisting the African American and International communities through education, lobbying, and economic initiatives, including Delta Days at the State and Nation's Capitol, Delta Days at the United Nations, Summits and various conferences which focus on pertinent issues of the day. In addition to establishing independent programming, The Sorority consistently collaborates with community and corporate organizations such as Chase, Habitat for Humanity, Coca-Cola, Wal-Mart, Lawry's, and General Electric to further its programming goals.

Delta-sigma modulation

Delta-sigma (ΔΣ; or sigma-delta, ΣΔ) modulation is a method for encoding analog signals into digital signals as found in an ADC. It is also used to transfer high bit-count low frequency digital signals into lower bit-count higher frequency digital signals as part of the process to convert digital signals into analog.

In a conventional ADC, an analog signal is integrated, or sampled, with a sampling frequency and subsequently quantized in a multi-level quantizer into a digital signal. This process introduces quantization error noise. The first step in a delta-sigma modulation is delta modulation. In delta modulation the change in the signal (its delta) is encoded, rather than the absolute value. The result is a stream of pulses, as opposed to a stream of numbers as is the case with PCM. In delta-sigma modulation, the accuracy of the modulation is improved by passing the digital output through a 1-bit DAC and adding (sigma) the resulting analog signal to the input signal, thereby reducing the error introduced by the delta-modulation.

Delta Sigma

Delta Sigma may refer to: