( Free42 ) Decibel Addition and Subtraction

[Gamo]

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.

Remark:
When Subtracting dB(1) < dB(2), the program will exchange values.

Gamo 6/1/2020