Location History:
- Woodland Hills, CA (US) (1976)
- Grass Valley, CA (US) (1989 - 1994)
Company Filing History:
3 out of 143 
2 out of 832,680 Years Active: 1976-1994
Title: The Innovative Contributions of Donald R Christensen
Introduction
Donald R Christensen is a notable inventor based in Grass Valley, CA (US). He has made significant contributions to the field of audio technology, holding a total of 5 patents. His work has influenced various aspects of video editing systems, particularly in audio mixing and crossfading techniques.
Latest Patents
One of Christensen's latest patents is a controller for a video editing system. This invention focuses on the shaping of automatic audio crossfade. The shaping of automatic audio crossfade is accomplished by adding a shaping function to the theoretical logarithmic crossfade function to decrease the rate of gain change at the limit of audibility. The gain change at each sample time within a crossfade interval is computed as a logarithmic function of the fractional part of the crossfade interval completed and the gain differential between the sources. The shaping function may be in the form of a cosine function that can be accessed with a look-up table that is added to the fractional part of the crossfade interval. This allows the gain change to be expressed by the formula: ti G.sub.delta =20*log{(k-s(k))*10.sup.(G.sbsp.1.sup.-G.sbsp.2.sup.)/10}. Here, S(k) is the shaping function, k is the fractional part complete, and G.sub.1 -G.sub.2 is the gain differential between sources. The gain change is added to the current gain for the particular audio source and applied to a variable gain element for that source. The outputs of the variable gain elements are summed to produce the resulting output audio mix.
Career Highlights
Throughout his career, Donald R Christensen has worked with various companies, including The Grass Valley Group, Inc. His expertise in audio technology has allowed him to develop innovative solutions that enhance video editing processes.
Collaborations
Christensen has collaborated with notable individuals in the industry, including Robert L Bateman and Thomas A Grancey. These collaborations have contributed to the advancement of audio technology and video editing systems.
Conclusion
Donald R Christensen's contributions to audio technology and video editing systems are noteworthy. His innovative patents and collaborations have significantly impacted the industry, showcasing his expertise and dedication to advancing technology.
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