hsp50415 Intersil Corporation, hsp50415 Datasheet - Page 8

• Manufacturer Part Number: hsp50415
• Description: Wideband Programmable Modulator Wpm
• Manufacturer: Intersil Corporation

The Lock Detector compares the magnitude of the
phaseError to a programmable 21-bit threshold value. If the
carry out from this comparison is “1” then the phaseError is
greater than or equal to the threshold value and a negative
value is added to the lock integrator. If the carry out is “0”
then the phaseError is less than the threshold and a positive
value is added. As the phaseError magnitude stays below
the threshold level the lock integrator will grow from a
negative number to a positive one thus indicating a locked
condition. The lock integrator resets to a full-scale negative
value. The sign bit of the lock integrator is output as the
LOCKDET status flag. The values added or subtracted to the
lock integrator are user selectable as follows in Table 2.
REFCLK divider<7:0>
negative notLockedValue
NCO divider<13:0>
phaseErrorMag<20:0>
analogPLLlockStatus
positive lockedValue
useAPLLlockStatus
phaseError<21:0>
threshold<20:0>
freqError<15:0>
frequencyGain
REFCLK
CLK
leadGain
lagGain
COUNTER
TC
SYNC
8-BIT
8
14-bit countValue
enable
_
FIGURE 2.
FIGURE 4.
COUNTER
carryOut
14-BIT
41
/
FIGURE 3.
PHASE/FREQUENCY ERROR DETECTOR
LIMITER
8 upper bits of phaseAccum
LOCK DETECTION BLOCK DIAGRAM
AO
A1
S
HSP50415
UL<31:0>
LL<13:0>
Z
DPLL LOOP FILTER
carryOut
R
R
LOCK FACTOR
AO
A1
S
SYMBOL NCO
bit=1 indicates phaseErr > thld so NOT
locked
Z
0xx
1xx
x00
x01
x10
x11
lockIntegrator<8>
TABLE 2. LOCK INTEGRATOR ADDENDS
R
CARRY OUT
1
1
0
0
0
0
R
R
-0.5
-0.25
+0.0625
+0.1250
+0.2500
+0.5000
_
ADDEND
DPLL
PhincError<31:0>
FIFOFreqError<8*7,7:0>
freqError<15:0>
phaseError<21:0>
LOCKDET
lockIntegrator<8:0>
BINARY VALUE
111111000
111111100
000000001
000000010
000000100
000001000
April 23, 2007
FN4559.6