參數(shù)資料
型號: SLWS132
廠商: Texas Instruments, Inc.
英文描述: QUAD RECEIVER CHIP
中文描述: 四接收器芯片
文件頁數(shù): 11/46頁
文件大?。?/td> 413K
代理商: SLWS132
GRAYCHIP, INC.
- 6 -
APRIL 27, 1999
GC4014 QUAD RECEIVER CHIP
DATA SHEET REV 0.6
This document contains information which may be changed at any time without notice
Figure 6 shows the maximum spur levels as the tuning frequency is scanned over a portion of the frequency
range with the peak hold function of the spectrum analyzer turned on. Notice that the peak spur level is -82 dB before
dithering and is between -92 and -102 after dithering has been turned on.
Figure 6. NCO Peak Spur Scan Plot
The worst case NCO spurs at -92 dB, such as the one shown in figure 6(b), are due to a few frequencies
that are related to the sampling frequency by small rational numbers (for example FREQ = 3/16 * Fck). In these
cases the rounding errors in the sine/cosine lookup table repeat in a regular fashion, thereby concentrating the error
power into a single frequency, rather than spreading it across the spectrum. These worst case spurs can be
eliminated by selecting an initial phase that minimizes the errors or by changing the tuning frequency by a small
amount (50 Hz). All spurs can be made to fall below -96 dB with the selection of a proper initial phase or tuning
frequency.
3.3.2
Four Stage CIC Filter
The mixer outputs are decimated by a factor of N in a four stage CIC filter, where N is any integer between
8 and 16,384. The programmable decimation allows the chip’s usable output bandwidth to range from less than a
kilo-Hertz to 1.5 MHz when the input rate (which is equal to the chip’s clock rate) is 62.5 MHz. A block diagram of
the CIC filter is shown in Figure 7.
Figure 7. Four Stage CIC Decimate by N Filter
The CIC filter has a gain equal to N
4
which must be compensated for in the “CIC_SCALE” circuit shown in
Figure 7. This circuit has a gain equal to 2
(SCALE+6*BIG_SCALE-56)
, where SCALE ranges from 0 to 5 and BIG_SCALE
ranges from 0 to 7. The gain of the CIC circuit is equal to:
. The user must select
values for SCALE and BIG_SCALE such that GAIN is less than one, i.e., SCALE and BIG_SCALE must be selected
such that:
. Overflows due to improper gain settings will go undetected if this
relationship is violated. For example, if N is equal to 8, then this restriction means that BIG_SCALE and SCALE
(a) Before Dithering
(b) After Dithering
-92 dB
-102 dB
-82 dB
UPPER
24 BITS
C
DIN
OUT
D
B
O
CLOCKED AT FULL RATE
CLOCKED AT 1/N RATE
16 BITS
GAIN
N
4
2
SCALE
6
BIG_SCALE
56
×
+
(
)
=
SCALE
6
BIG_SCALE
×
+
(
)
56
4log
2
N
(
)
相關PDF資料
PDF描述
SM-762A DC Tachometer Generators
SM-762B DC Tachometer Generators
SM-A2847 CRYSTAL CLOCK OSCILLATORS
SM-A284C CRYSTAL CLOCK OSCILLATORS
SM-2840 CRYSTAL CLOCK OSCILLATORS
相關代理商/技術參數(shù)
參數(shù)描述
SLWSTK6000A 功能描述:DEV KIT WIRELESS EFR32MG 2.4GHZ 制造商:silicon labs 系列:Mighty Gecko 零件狀態(tài):有效 類型:收發(fā)器; 智能低功耗(BLE)藍牙? 4.x 頻率:2.4GHz 配套使用產(chǎn)品/相關產(chǎn)品:EFR32MG 所含物品:9 板,線纜,配件 標準包裝:1
SLWSTK6000B 功能描述:EFR32MG12 2.4GHZ MESH KIT 制造商:silicon labs 系列:Mighty Gecko 零件狀態(tài):在售 類型:收發(fā)器; 802.15.4(線程, ZigBee?) 頻率:2.4GHz 配套使用產(chǎn)品/相關產(chǎn)品:EFR32MG12 所含物品:板 標準包裝:1
SLWSTK6020A 功能描述:DEV KIT BLE EFR32BG 2.4GHZ 制造商:silicon labs 系列:Blue Gecko 零件狀態(tài):有效 類型:收發(fā)器; 智能低功耗(BLE)藍牙? 4.x 頻率:2.4GHz 配套使用產(chǎn)品/相關產(chǎn)品:EFR32BG 所含物品:3 板,線纜,配件 標準包裝:1
SLWSTK6020B 功能描述:EFR32 BLUE GECKO BLUETOOTH START 制造商:silicon labs 系列:Blue Gecko 零件狀態(tài):在售 類型:收發(fā)器; 智能低功耗(BLE)藍牙? 4.x 頻率:2.4GHz 配套使用產(chǎn)品/相關產(chǎn)品:EFR32BG13 所含物品:板 標準包裝:1
SLWSTK6060A 功能描述:DEV KIT EFR32FG 915MHZ 2.4GHZ 制造商:silicon labs 系列:Flex Gecko 零件狀態(tài):在售 類型:收發(fā)器 頻率:915MHz, 2.4GHz 配套使用產(chǎn)品/相關產(chǎn)品:EFR32FG 所含物品:板 標準包裝:1