參數(shù)資料
型號(hào)： CLC5903
廠商： National Semiconductor Corporation
英文描述： Dual Digital Tuner / AGC
中文描述： 雙數(shù)字調(diào)諧器/自動(dòng)增益控制
文件頁(yè)數(shù)： 20/29頁(yè)
文件大?。?/td> 698K
代理商： CLC5903
www.national.com
20
C
level. DVGA operation results in a compression of the signal
through the ADC. The DVGA signal compression is reversed
in the CLC5903 to provide > 120dB of linear dynamic range.
This is illustrated in Figure 32.
In order to use the AGC, the DRCS Control Panel software
may be used to calculate the programmable parameters. To
generate these parameters, only the desired setpoint, dead-
band+hysteresis, and loop time constant need to be sup-
plied. All subsequent calculations are performed by the
software. Complete details of the AGC operation are pro-
vided in an appendix but are not required reading.
AGC setpoint and deadband+hysteresis are illustrated in Fig-
ure 33. The loop time constant is a measure of how fast the
loop will track a changing signal. Values down to approxi-
mately 1.0 microsecond will be stable with the second order
LC noise filter. Since the DVGA operates with 6dB steps the
deadband should always be greater than 6dB to prevent
oscillation. An increased deadband value will reduce the
amount of AGC operation. A decreased deadband value will
increase the amount of AGC operation but will hold the ADC
output closer to the setpoint. The threshold should be set so
that transients do not cause sustained overrange at the ADC
inputs. The threshold setting can also be used to set the
ADC input near its optimal performance level.
The AGC will free run when AGC_HOLD_IC is set to ‘0’. It
may be set to a fixed gain by setting AGC_HOLD_IC to ‘1’
after programming the desired gain in the AGC_IC_A and
AGC_IC_B registers. Allowing the AGC to free run should be
appropriate for most applications.
Programming the AGC_COMB_ORD register allows the
AGC power detector bandwidth to be reduced if desired. This
will tend to improve the power detector’s ability to reject the
signal carrier frequency and reduce overall AGC activity. Fig-
ure 36 on page 24 shows the power detector response.
Power Management
The CLC5903 can be placed in a low power (static) state by
stopping the input clock. To prevent this from placing the
CLC5903 into unexpected states, the
SI
pin of the CLC5903
should be asserted prior to disabling the input clock and held
asserted until the input clock has returned to a stable condi-
tion.
Test and Diagnostics
The CLC5903 supports IEEE 1149.1 compliant JTAG Bound-
ary Scan for the I/O's. The following pins are used:
TRST (test reset)
TMS
(test mode select)
TDI
(test data in)
TDO
(test data out)
TCK
(test clock)
The following JTAG instructions are supported:
The JTAG Boundary Scan can be used to verify printed cir-
cuit board continuity at the system level.
The user is able to program a value into TEST_REG and
substitute this for the normal channel inputs from the
AIN/
BIN
pins by selecting it with the crossbar. With the NCO fre-
quency set to zero this allows the DDCs and the output inter-
face of the chip to be verified. Also, the AGC loop can be
opened by setting AGC_HOLD_IC high and setting the gain
of the DVGA by programming the appropriate value into the
AGC_IC_A/B register.
Real-time access to the following signals is provided by con-
figuring the control interface debug register:
NCO sine and cosine outputs
data after round following mixers
data before F1 and F2
data after the CIC filter within the AGC
The access points are multiplexed to a 20-bit parallel output
port which is created from signal pins
POUT[15:0]
,
AOUT
,
BOUT
,
SFS
, and
RDY
according to the table below:
Figure 32. Output Gain Scaling vs. Input Signal
Input Power
ADC Output
ADC Full Scale
Deadband+Hysteresis
O
DDCOupu
Diversity Receiver
Chipset Full Scale
Ove ThsRange
Figure 33. AGC Setup.
DVGA Input Power
D
Deadband
Hysteresis=Deadband-6dB
Reference
Setpoint
6
6dB
Instruction
Description
BYPASS
Connects TDI directly to TDO
EXTEST
Drives the ‘extest’ TAP controller output
IDCODE
Connects the 32-bit ID register to TDO
SAMPLE/PRELOAD
Drives the ‘samp_load’ TAP controller
output
HIGHZ
Tri-states the outputs
Normal Mode Pin
Debug Mode Pin
POUT[15:0]
DEBUG[19..4]
RDY
DEBUG[3]
SFS
DEBUG[2]
AOUT
DEBUG[1]
BOUT
DEBUG[0]
Test and Diagnostics
(Continued)
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CLC5903CISM/NOPB 功能描述:上下轉(zhuǎn)換器 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128
CLC5903SM 功能描述:上下轉(zhuǎn)換器 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128
CLC5903SM/NOPB 功能描述:上下轉(zhuǎn)換器 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128
CLC5903VLA 功能描述:上下轉(zhuǎn)換器 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128
CLC5903VLA/NOPB 功能描述:上下轉(zhuǎn)換器 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Down Converters 射頻:52 MHz to 78 MHz 中頻:300 MHz LO頻率: 功率增益: P1dB: 工作電源電壓:1.8 V, 3.3 V 工作電源電流:120 mA 最大功率耗散:1 W 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFP-128
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