AD6654/PCB Analog Devices Inc, AD6654/PCB Datasheet - Page 82

• Manufacturer Part Number: AD6654/PCB
• Description: BOARD EVALUATION FOR AD6654
• Manufacturer: Analog Devices Inc

Specifications of AD6654/PCB

• Module/board Type: Evaluation Board
• For Use With/related Products: AD6554
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD6654
format of the AGC error threshold register is four bits to the left
of the binary point and eight bits to the right.
See the Automatic Gain Control section for details.
AGC Average Samples <5:0>
This 6-bit register contains the scale used for the CIC filter and
the number of power samples to be averaged before being sent
to the CIC filter.
<5:2>: CIC Scale. This 4-bit word defines the scale used for the
CIC filter. Each increment of this word increases the CIC scale
by 6.02 dB.
<1:0>: Number of AGC Average Samples. This defines the
number of samples to be averaged before they are sent to the
CIC decimating filter. See Table 41.
Table 41. Number of AGC Average Samples
AGC Average Samples <1:0>
00
01
10
11
AGC Pole Location <7:0>
This 8-bit register is used to define P, the open-loop filter pole
location. Its value can be set from 0 to 0.996 in steps of 0.0039.
This value of P is updated in the AGC loop each time the AGC
is initialized. This open-loop pole location directly impacts the
closed-loop pole locations, as explained in the Automatic Gain
Control section.
AGC Desired Level <7:0>
This register contains the desired signal level or desired clipping
level, depending on operational mode. This desired request
level (R) can be set in dB from 0 to 23.99 in steps of 0.094 dB.
The request level (R) in dB should be converted to a register
setting using the following formula:
AGC Loop Gain 2 <7:0>
This 8-bit register is used to define K
open-loop gain. Its value can be set from 0 to 0.996 in steps of
0.0039. This value of K
initialized. When the magnitude-of-error signal in the loop is
greater than the AGC error threshold, then K
loop. K
Register
Register
2
is updated only when the AGC is initialized.
Value
Value
=
=
round
round
2
is updated each time the AGC is
⎡
⎢
⎢
⎣
⎡
⎢
⎢
⎣
20
Error
20
log
Number of Samples Taken
1
2
3
4
log
R
Threshold
10
2
, the second possible
10
(
) 2
(
) 2
×
64
2
⎤
⎥
⎥
⎦
is used by the
⎤
⎥
⎥
⎦
×
256
Rev. 0 | Page 82 of 88
AGC Loop Gain 1 <7:0>
This 8-bit register is used to define K
value can be set from 0 to 0.996 in steps of 0.0039. This value of
K is updated in the AGC loop each time the AGC is initialized.
When the magnitude-of-error signal in the loop is less than the
AGC error threshold, then K
only when the AGC is initialized.
I Path Signature Register <15:0>
This 16-bit signature register is for the I path of the channel
logic. The signature register records data on the networks that
leave the channel logic, just before entering the second data
router.
Q Path Signature Register <15:0>
This 16-bit signature register is for the Q path of the channel
logic. The signature register records data on the networks that
leave the channel logic, just before entering the second data
router.
BIST Control <15:0>
<15>: Disable Signature Generation Bit. When this bit is active
high, the signature registers do not produce a pseudorandom
output value, but instead directly load the 24-bit input data.
When this bit is cleared, the signature register produces a
pseudorandom output for every clock cycle that it is active. See
the User-Configurable Built-In Self-Test (BIST) section for
details.
<14:0>: BIST Timer Bits. The <14:0> bits of this register form a
15-bit word that is loaded into the BIST timer. After loading the
BIST timer, the signature register is enabled for operation while
the timer is actively counting down. See the User-Configurable
Built-In Self-Test (BIST) section for details.
OUTPUT PORT REGISTER MAP
This part of the memory map deals with the output data and
controls for parallel output ports.
Parallel Port Output Control <23:0>
<23>: Port C Append RSSI Bit. When this bit is set, an RSSI
word is appended to every I/Q output sample, regardless of
whether the RSSI word is updated in the AGC. When this bit is
cleared, an RSSI word is appended to an I/Q output sample only
when the RSSI word is updated. The RSSI word is not output for
subsequent I/Q samples until the next time the RSSI is updated
in the AGC.
<22>: Port C, Data Format Bit. When this bit is set, the port is
configured for 8-bit parallel I/Q mode. When cleared, the port
is configured for 16-bit interleaved I/Q mode. See the Parallel
Port Output section for details.
<21>: Port C, AGC5 Enable Bit. When this bit is set, AGC5
data (I/Q data) is output on parallel Output Port C (data bus).
1
is used by the loop. K
1
, the open-loop gain. Its
1
is updated