My question deals specifically with filling out Form M-8 in Annex M. I have managed to get the "a,b,c,d and e" rows filled in although I am not sure about row e. In the supplemental instructions it states: The Collective dB Error "e" is established by starting with the dB Error "d" nearest to 0.0, collectively add the dB Error "d" values horizontally, placing the subtotals in Row "e". Yet in the example below the instructions 0.0 is established twice. Once under row 8 and again under row 10. In this example they choose to use row 10 as the starting point. Why????
Also in the next supplemental instruction it states: Moving horizontally, left and right from the Average % line, find the span in which the largest and smallest Collective dB Error figures remain at or below 2 dB. Count the number of horizontal spaces of movement, subtract one, and multiply the remainder by six. This dB value is the acceptable range of the unit.
I do not understand this. First of all, in the example below they have stated the "Accuracy required: Minimum allowable range is 60 dB.
In order to get the 60 dB they need 11 horizontal spaces of movement, subtract one and multiply by 6= 60dB. How did they do this????? Where is the 11 horizontal spaces???
Other questions I have regarding this statement:
What is the Average % line exactly????
It states to find the Collective dB Error figures at or below 2 dB. In the example below all the Collective dB Error entries are below 2 dB. (Row one is -2.2)
Also how can a single dB value be an acceptable "range"..... A range is a space inbetween two points.
I assume that this information is to be entered below in the "Total qualified range" (From the chart above)
The next line is also "Total qualified range" (From Form M-9)
I am have been told that AWS uses this dB accuracy in place of... or to obtain a vertical linearity and that this qualification is intended more to a older analog unit.......
It is very hard for me to understand.
If anyone can enlighten me, I would appreciate it. Thank you.
Walt,
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