- 您现在的位置：买卖IC网 > PDF目录385871 > ST7285C (意法半导体) 8-BIT MCU FOR RDS WITH 48K ROM, 3K RAM, ADC, TWO TIMERS, TWO SPIs, I2C AND SCI INTERFACES PDF资料下载
参数资料
| 型号： | ST7285C |
| 厂商： | 意法半导体 |
| 英文描述： | 8-BIT MCU FOR RDS WITH 48K ROM, 3K RAM, ADC, TWO TIMERS, TWO SPIs, I2C AND SCI INTERFACES |
| 中文描述： | 8位微控制器48,000铁路发展策略光盘，3K内存，ADC，两个定时器，2个SPI，I2C和脊髓损伤接口 |
| 文件页数： | 69/117页 |
| 文件大小： | 748K |
| 代理商： | ST7285C |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页当前第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页第115页第116页第117页
69/117
ST7285C
RDS DEMODULATOR
(Cont’d)
4.8.2 Functional Description
The RDS Demodulator is fed with a 57KHz band-
pass filtered and limited multiplex signal.
It contains the following functional blocks:
–
57kHz PL
L. This circuit is implemented as a var-
iable counter controlled by a “COSTAS” phase
comparator. To achieve fast lockup time, thelow-
pass filter features four software selectable time
constants. Following a reset, the longest time
constant is selected and used for the locked con-
dition. The time constant relates to the time
needed to compensate a 90 degree phase devi-
ation. As the PLL locks to 0 and 180 degrees,
whatever is closest, this is the maximum possible
phase deviation. The selectable time constants
are listed in the following register description.
–
1187.5Hz PLL
. This circuit detects zero cross-
ings of the phase of the input signal. After low
pass filtering, this information is used to control a
variable divider, which generates the RDS clock.
The timeconstant of the low pass filter is also se-
lectable in four steps.
The regulation of both PLLs may be inhibited by
software. This may be used to “freeze” the actual
phase relation in order to bridge a certain time of
weak or non-existing input signal. (e.g. during AF
tests, breakdown in field strength,...). Depending
of the precision of the quartz oscillator some sec-
onds of weak input signal may be spanned with-
out loosing the lock condition.
–
“Polarity” Phase Decoder
. With the help o the
recovered 57kHz carrier, the sign of theinput sig-
nal phase is integrated over one bit (48 sam-
ples).
–
“Integral” Phase Decoder
. The relative phase
angle of the input signal to the recovered carrier
is measured. Again 48 samples are accumulat-
ed. Regarding of the “polarity phase decoder,
this system is less sensitive to the precision of
the recovered carrier, but is more sensitive with
respect to ignition spikes.
–
Differential Decoder
. Every phase decoder out-
put is fed into itsown differential decoder. For er-
ror correction purposes, a quality bit can be
generated in order to mark all differences be-
tween the two decoder outputs.
–
QualityDetector
.Thisunitmeasures theamount
of opposite phase samples. With anerror freesig-
nal; every bit consists of 24 positive and 24 neg-
ative phase samples related to the carrier. Dueto
noise, this balance may be disturbed. all bits with
a relation greater than 40 to 8 are marked as bad.
This quality information may be used by the soft-
ware foran improved error correction. Italso may
be used internally (selection by software) to
switch automatically between “polarity” and “inte-
gral” phase decoders.
The source of RDS data may be one or the other
output of these two decoders.
The source of the quality output may be selected
from the quality detector or from the exor which
builds the difference between the two differential
decoders.
–
ARI Indicator
. In order to receive a correct RDS
signal,the57KHzPLLregulation mustbechanged
inaccordance withthepresence ofARI.Therefore
a fast ARI indicator is implemented. This function
may be optionally taken over by software.
–
Interface Registers
. These allow control of the
Demodulator circuit by the MCU. Register de-
scriptions are given below:
相关PDF资料 |
PDF描述 |
|---|---|
| ST72T85A5Q6 | 8-BIT MCU FOR RDS WITH 48K ROM, 3K RAM, ADC, TWO TIMERS, TWO SPIs, I2C AND SCI INTERFACES |
| ST730C08L3 | PHASE CONTROL THYRISTORS |
| ST730C08L3L | PHASE CONTROL THYRISTORS |
| ST730C12L0 | PHASE CONTROL THYRISTORS |
| ST730C12L0L | PHASE CONTROL THYRISTORS |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ST7-28B56 | 功能描述:电源变压器 SPLIT BOBBIN HORZ MOUNT XFMR RoHS:否 制造商:Triad Magnetics 功率额定值:12 VA 初级电压额定值:115 V / 230 V 次级电压额定值:12 V / 24 V 安装风格:SMD/SMT 一次绕组:Dual Primary Winding 二次绕组:Dual Secondary Winding 长度:2.5 in 宽度:2 in 高度:1.062 in |
| ST72A | 制造商:DGS 功能描述: |
| ST72C104G1B6 | 功能描述:8位微控制器 -MCU Flash 4K SPI RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| ST72C104G1M1 | 制造商:STMicroelectronics 功能描述:8-BIT MICROCONTROLLER - Bulk |
| ST72C104G1M6 | 功能描述:8位微控制器 -MCU Flash 4K SPI RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
发布紧急采购，3分钟左右您将得到回复。