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+--- Thread: ( Free42 ) Decibel Addition and Subtraction (/thread-15110.html)
( Free42 ) Decibel Addition and Subtraction - Gamo - 06-01-2020 12:50 PM
This program is adapted from
HP-41C Heating, Ventilation and Air Conditioning Page 65
Assign [dB-] and [dB+] to Soft Menu
Example 1:
A noise level of 72 dB is measured in a room.
The air conditioning is turned on and
the noise level increases to 74 dB
What is the noise level of the air conditioning system.
[FIX] 02
74 [ENTER] 72 [dB-] display 69.67 dB
Example 2:
A compressor is known to have a sound pressure level of 90 dB.
The background noise is 85 dB. What is the total?
90 [ENTER] 85 [dB+] display 91.19 dB
-----------------------------------------------------------------------
Program:
Code:
00 { 51-Byte Prgm }
01 LBL "dB+"
02 XEQ 00
03 +
04 GTO 01
---------------------- Add Decibels.
05 LBL "dB-"
06 XEQ 00
07 -
08 ABS
---------------------- Subtract Decibels.
09 LBL 01
10 LOG
11 10
12 x
13 CLA
14 ARCL ST X
15 ⊢"dB"
16 AVIEW
17 RTN
--------------------- Display Result.
18 LBL 00
19 10
20 STO÷ ST Z
21 ÷
22 X<>Y
23 10↑X
24 X<>Y
25 10↑X
--------------------- Convert for Add or Subtract.When Subtracting dB(1) < dB(2), the program will exchange values.
Gamo 6/1/2020