Telit Wireless Solutions LE910 - Audio Filters; Uplink Path Biquad Filters - #BIQUADIN

Telit LE910 V2 Series AT Commands
80446ST10707A Rev. 0– 2015-11-03
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 458 of 509
Mod. 0808 2011-07 Rev.2
Audio Filters
Uplink Path Biquad Filters - #BIQUADIN
#BIQUADIN - Uplink Path Biquad Filters
SELINT 2
AT# BIQUADIN=
<a
F0
>
[,<a
F1
>
[,<a
F2
>
[,<b
F1
>
[,<b
F2
>
[,<a
S0
>
[,<a
S1
>
[,<a
S2
>
[,<b
S1
>
[,<b
S2
>
]]]]]]]]]
Set command allows to configure the parameters of the two cascaded
digital biquad filters
)()( zHzH
SecondFirst
⋅
in Uplink path (sending). It is
not allowed if active audio profile is 0.
Parameters:
<a
Fn
>,<b
Fn
>,<a
Sn
>,<b
Sn
> - they all are specific parameters for the
calculation of digital biquad filters as follows:
2
2
1
1
2
2
1
10
21
2
)(
−−
−−
⋅+⋅⋅+
⋅+⋅⋅+
=
zbzb
zazaa
zH
FF
FFF
F
2
2
1
1
2
2
1
10
21
2
)(
−−
−−
⋅+⋅⋅+
⋅+⋅⋅+
=
zbzb
zazaa
zH
SS
SSS
S
-32768..32767 - each value has to be interpreted as signed fixed point
number in two’s complement format with 15 fractional
bits in a 16 bit word (Q15)
Note: in the above formulas pay attention to the multiplier (2) for
parameters <a
F1
>, <a
S1
>, <b
F1
> and <b
S1
>
Parameters can be saved in NVM using AT#PSAV command and are
available for audio profiles 1,2,3. For audio profile 0 the values are fixed.
AT# BIQUADIN?
Read command returns the parameters for the active profile in the format:
#BIQUADIN:
<a
F0
>,<a
F1
>,<a
F2
>,<b
F1
>,<b
F2
>,<a
S0
>,<a
S1
>,<a
S2
>,<b
S1
>,<b
S2
>
It is not allowed if active audio profile is 0.
AT# BIQUADIN=?
Test command returns the supported range of values for parameters <a
F0
>,
<a
F1
>, <a
F2
>, <b
F1
>, <b
F2
>, <a
S0
>, <a
S1
>, <a
S2
>, <b
S1
>, <b
S2
>