| 80 |
Historically, the parameter of bandwidth in radioastronomical receiver used to be within the kilohertz range. Small bandwidth was acceptable because observations were processed directly by listening or by paper chart intensity recorder. Chart recorder integrated energy of signal over defined small bandwidth which was suitable for detecting the intensity variance of microwave background. No wideband transmitters existed in that era (except for TV transmitters) and tuning to other neighbouring frequency was easy as they were mostly vacant. Parallel observations from several places were unnecessary as well because the electromagnetic conditions were nearly same at all locations.
|
80 |
Historically, the parameter of bandwidth in radioastronomical receiver used to be within the kilohertz range. Small bandwidth was acceptable because observations were processed directly by listening or by paper chart intensity recorder. Chart recorder integrated energy of signal over defined small bandwidth which was suitable for detecting the intensity variance of microwave background. No wideband transmitters existed in that era (except for TV transmitters) and tuning to other neighbouring frequency was easy as they were mostly vacant. Parallel observations from several places were unnecessary as well because the electromagnetic conditions were nearly same at all locations.
|
| 87 |
Professional astronomers use proprietary digitalisation units \url{http://arxiv.org/abs/1305.3550} or by multichannel sound cadrd on amateur levels \url{http://fringes.org/}
|
87 |
Professional astronomers use proprietary digitalisation units \url{http://arxiv.org/abs/1305.3550} or by multichannel sound cadrd on amateur levels \url{http://fringes.org/}
|