- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄67672 > GP2000 (Mitel Networks Corporation) () PDF資料下載
參數(shù)資料
| 型號(hào)： | GP2000 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | () |
| 中文描述： | （） |
| 文件頁數(shù)： | 20/25頁 |
| 文件大小： | 256K |
| 代理商： | GP2000 |
4
GP2000 – GPS CHIPSET DESIGNER’S GUIDE
Fig. 4 Application circuit
second IF of 3542 MHz. This places the image at 10458MHz.
Attenuation of the image is achieved via a 17542MHz
bandpass (61MHz) filter before the second stage mixer. This
complements any image attenuation at this frequency from the
antenna and RF filter.
Third Stage
The third stage of signal down-conversion mixes the signal
at 3542MHz with a local oscillator at 31111MHz to give a third
IF of 4309MHz, placing the image at 26802MHz.
The AGC operates such that the magnitude bit (MAG) at the
output of the 2-bit A-to-D converter is high for nominally 30% of
the time. When the magnitude bit is high it is given a value of 3.
When low it is given a value of 1. The SIGN bit will be high for
nominally 50% of the time. This statistical distribution of data
aids the system in suppressing CW interference.
Signal Down-Conversion Sampling
The signal at its third IF of 4309MHz is then sampled and
latched at the SIGN and MAG outputs. When used with the
GP2021 the sampling clock is at 5714MHz. The aliasing present
in the sampling process produces a final digital signal at an IF of
nominally 1405 MHz (Fig. 6).
Power Supplies
The analog and digital sections of the device can be oper-
ated from separate power supplies to prevent interaction with
digital switching transitions in the analog section.
The GP2015 includes an on-chip voltage detector for the
digital supply. This drives a logic output which goes high when
the power supply has reached a nominal value. This output can
be used to disable the correlator and microprocessor when power
supply switching is occurring.
The GP2015 can be put into a Power-Down mode where
most of the device, except the power supply switching detector,
is disabled. This changes the current consumption from nomi-
nally 70mA to 10mA.
The second IF filter is critical to system performance and
effectively sets the bandwidth of the front end. To achieve high
levels of image and interference rejection, a filter with a very
tight passband and sharp cut-off is required.
The use of a SAW filter, such as the GEC Plessey Semicon-
ductors DW9255, is recommended to achieve these types of
characteristic. The DW9255 has a 19MHz passband centred
on 3542MHz with 08dB of passband ripple and out-of-band
rejection of better than 21dB at 620MHz and better than 35dB
at 675MHz.
AGC and Sampling
Following the third stage mixer the signal is filtered with
an on-chip 43MHz passband (61MHz) filter. The signal is
then used to control the gain of the AGC which appears be-
tween the second IF filter and third stage mixer (Fig. 5). The
AGC caters for factors such as varying RF amplifier gain and
cable loss.
32
REF 2
10MHz I/P
GP2015 FRONT END
48 PIN
175MHz
FILTER
VCC
L1
L2
40
41
37
38
CP
CS
RF
INPUT
C1
C2
R1
27
POWER_GOOD
PLL LOCK
SIGN 0
MAG 0
SAMPCLK
CLK_I
CLK_T
GP2021
CORRELATOR
80 PIN
4, 6
9
21
14
15
11
16
17
2
66
77
76
73
71
70
CS = 12pF
CP = 27pF
PLL LOOP
FILTER:
CAGC = 01
VALUES FOR L1 AND L2 ARE
DEPENDENT ON FILTER USED
L3, L4 = 560nH
L5 = 22H
DW9255
SAW
FILTER
L3
L4
47
48
44
45
L5
30, 31,
33, 34
C1 = 047F
C2 = 10nF
R1 = 270
2
3
RF INPUT
MATCHING:
CREG = 01F
(VCC = 15V ONLY)
POWER-ON
REF
R2
R3
POWER-ON REF
LADDER
R3 = 27k
R2 = 27k (VCC = 130V)
= 68k (VCC = 150V)
VCC
8
23
24
R6
R5
R4
R4 = 470
R5 = 470
R6 = 15k
PRESET
LD
SIGN
MAG
CLK
OPCLK2
OPCLK1
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| GP2010 | GPS Receiver RF Front End |
| GP2010 | GPS Receiver RF Front End(用于全球定位系統(tǒng)（GPS）接收器的第二代RF前端) |
| GP2015 | Aluminum Electrolytic Radial Leaded Low Profile Wide Temp Capacitor; Capacitance: 22uF; Voltage: 25V; Case Size: 5x9 mm; Packaging: Bulk |
| GP2015 | GPS Receiver RF Front End(用于全球定位系統(tǒng)（GPS）接收器的第二代RF前端) |
| GP2021 | GPS 12 channel Correlator(用于全球定位系統(tǒng)（GPS）接收器的12通道的C/A代碼基帶相關(guān)器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| GP20-005R | 制造商:FRONTIER 制造商全稱:Frontier Electronics. 功能描述:2A GENERAL PURPOSE PLASTIC RECTIFIER |
| GP2000-D11-L25-0.3 | 制造商:t-Global Technology 功能描述:THERMAL PAD TUBE 11X25X0.3MM |
| GP2000-D11-L30-0.3 | 制造商:t-Global Technology 功能描述:THERMAL PAD TUBE 11X30X0.3MM |
| GP2000-D13.5-L25-0.3 | 制造商:t-Global Technology 功能描述:THERMAL PAD TUBE 13.5X25X0.3MM |
| GP2000-D13.5-L30-0.3 | 功能描述:THERMAL PAD TUBE 13.5X30X0.3MM 制造商:t-global technology 系列:GP2000 零件狀態(tài):有效 使用:- 形狀:圓形 外形:30.00mm x 13.50mm 厚度:0.012"（0.305mm） 材料:硅樹脂橡膠 粘合劑:- 底布，載體:- 顏色:綠 熱阻率:- 導(dǎo)熱率:1.3 W/m-K 標(biāo)準(zhǔn)包裝:1 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。