User guide

9 - 2
PN 074-566-P1B
Composer Elite Operating Manual
Composer Elite determines the speed of sound by precisely determining the gases’
fundamental resonant frequency in a fixed chamber of length
L. At resonance, a
standing half wave exists in the Resonant Chamber, so the speed of sound and
frequency are related as follows:
[6]
In practice, the exact value of
L is unimportant. Composition is computed from
knowledge of the mixture's frequency relative to the frequency of the pure gas as
follows. Let:
[7]
[8]
[9]
Applying equations 7, 8, and 9 into equations 3 and 4 yields,
[10]
[11]
If we define the speed of sound in the majority, or carrier, gas as
C
2
[12]
and apply equations 9 and 10 into equation 4 we get:
[13]
Since the speed of sound in a fixed resonator is directly proportional to the
frequency of resonance, we define a ratio:
[14]
f
C
2L
-------=
m
M
1
M
2
--------=
g

1

2
-----=
h
1

2
-----=
MM
2
m1–x1+=
 1=

2
gh–1h–
x1 g–gh–+
--------------------------------------------------+
C
2

2
RT
M
2
-------------=
c
2
c
2
2
h
gh–1h–
x1 g–gh–+
-------------------------------------------+


1m1–x+
1–
=

C
C
2
------


2
f
f
2
----


2
==