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| 型號： | U4222B |
| 英文描述： | Radio Controlled Clock Receiver |
| 中文描述： | 電波鐘接收器 |
| 文件頁數(shù)： | 3/9頁 |
| 文件大小： | 98K |
| 代理商： | U4222B |
TELEFUNKEN Semiconductors
U4222B
Preliminary Information
Rev. A1: 13.08.1996
3 (9)
TCO
The digitized serial signal of the time code transmitter can
be directly decoded by a microcomputer. Details about
the time code format of several transmitters are described
separately. The output consists of a PNP current source
and a NPN switching transistor T
S
. The guaranteed source
output current is 0.2
μ
A (TCO = high) and the sink current
is 1
μ
A (TCO = low). Considering these output currents,
the supply voltage and the switching levels of the
following
μ
C, the lowest load resistance is defined. The
maximum load capacitance is 100 pF.
In order to improve the driving capability an external
pull–up resistor can be used. The value of the resistor
should be 4.7 M . To prevent an undefined output voltage
in the power–down state of the U4222B, the use of this
pull–up resistor is recommended.
An additional improvement of the driving capability may
be achieved by using a CMOS driver circuit or a NPN
transistor with pull–up resistor connected to the collector
(see figure 2.). Using a CMOS driver this circuit must be
connected to V
CCD
.
pin 9
100 k
V
CCD
pin13
TCO
4.7 M
TCO
TS
I
SOURCE
0.2 A
I
SINK
1 A
93 7689 e
Figure 2.
Functional Description
The following description gives you some additional in-
formation and hints in order to facilitate your design, in
particular the problems of the antenna.
Figure 3. shows the principal function of the receiver
(simplified consideration).
res
R
Demodulator
Comparator
CF
A1
93 7521 e
A 2 and
Figure 3.
R
res
: resonant resistance, A1: preamplifier,
A2: amplifier 2, CF: crystal filter
Condition for signal reception:
S/N
≈
4 at comparator input.
Important parameters are:
V
NA
= (4 k T R
res
)
1/2
BW
A
= f
res
/Q
A
input noise voltage density of preamplifier:
V
NA1
: 40 nV/Hz
1/2
(typ)
bandwidth of preamplifier:
BW
A1
: 60 kHz (typ)
bandwidth of crystal filter:
BW
CF
: 16 Hz (typ)
ultimate attenuation of crystal filter:
D
CF
: –35 dB (typ)
whereas:
V
NA
k
T
BW
A
bandwidth of antenna
f
res
resonant frequency
Q
A
Q antenna
antenna noise voltage density
1.38 10
–23
Ws/K (Boltzmann constant)
absolute temperature
The equivalent input noise voltage at the preamplifier
input is:
V
N
V
NA
BW
CF
2
V
NA
BW
A
D
CF
2
V
NA1
BW
CF
2
V
NA1
BW
A1
D
CF
2
whereas:
R
res
= 300 k , BW
A
= 1 kHz then V
N
≈
0.4 V
The condition for signal reception is:
S/N
≈
4
sensitivity
≈
1.6 V
That means that the noise voltage of antenna within the
bandwidth of the crystal filter dominates and the
bandwidth of antenna is uncritical for the sensitivity
aspect.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| U4222B-CFPG1 | Radio Controlled Clock Receiver |
| U4223B-BFL | Voltage comparators |
| U4223B-BFS | Voltage comparators |
| U4223B-CFS | Low power quad voltage comparator |
| U4223B-CFSG3 | Remote-Control Receiver/Decoder |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| U4222B-CFP | 制造商:TEMIC 制造商全稱:TEMIC Semiconductors 功能描述:Radio Controlled Clock Receiver |
| U4222B-CFPG1 | 制造商:TEMIC 制造商全稱:TEMIC Semiconductors 功能描述:Radio Controlled Clock Receiver |
| U4223B | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Time-Code Receiver with A/D Converter |
| U4223B-BFL | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Peripheral IC |
| U4223B-BFS | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Peripheral IC |
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