Location
Cocoa Beach, FL
Start Date
5-4-1965 8:00 AM
Description
Three typical channels of Rocket Booster data have been studied to determine the amount of bandwidth reduction that is possible with an adaptive telemeter. The three channels included a flow measurement, a temperature measurement and an ignition pressure measurement. The time period studied was 220 seconds, starting 142. 583 seconds before first stage cut off, and for 77. 417 seconds after burn out. During this time 2640 ten-bit samples were taken on each channel. Therefore, the original data studied was composed of 79, 200 bits. The results of the study show that this could be reduced to 493 bits, when the peak-to-peak pickup on each channel is used as a means of determining the selection tolerance. This method includes two code words for each transmitted data word. One word of 8 bits to indicate which channel was being transmitted and a second code word of 10 bits of timing. In other words, a reduction of 161 to 1 is possible without the loss of any data. The total PCM system was composed of 216 ten-bit channels, each sampled 12 times per second. This would require a video bandwidth of about 13 KC. If the three channels studied are an indication of the average reduction, this bandwidth could be reduced to about 80 cps of binary transmission.
Data Compaction of Rocket Booster PCM Telemtry Data
Cocoa Beach, FL
Three typical channels of Rocket Booster data have been studied to determine the amount of bandwidth reduction that is possible with an adaptive telemeter. The three channels included a flow measurement, a temperature measurement and an ignition pressure measurement. The time period studied was 220 seconds, starting 142. 583 seconds before first stage cut off, and for 77. 417 seconds after burn out. During this time 2640 ten-bit samples were taken on each channel. Therefore, the original data studied was composed of 79, 200 bits. The results of the study show that this could be reduced to 493 bits, when the peak-to-peak pickup on each channel is used as a means of determining the selection tolerance. This method includes two code words for each transmitted data word. One word of 8 bits to indicate which channel was being transmitted and a second code word of 10 bits of timing. In other words, a reduction of 161 to 1 is possible without the loss of any data. The total PCM system was composed of 216 ten-bit channels, each sampled 12 times per second. This would require a video bandwidth of about 13 KC. If the three channels studied are an indication of the average reduction, this bandwidth could be reduced to about 80 cps of binary transmission.
