关于电力线载波芯片ST7538的一些问答
在线问答：[问：pengq318] 我们在毕业时做了电力通信设计，是用单片机模拟时钟，有受到电力干扰，不知道贵芯片有这方面的抑制功能没有啊？
[答：Peng] 芯片内部集成了滤波和保护电路，对电力线上的干扰有过滤作用。但是更重要的是外围滤波电路的设计和系统的设计，以及电路板设计，尤其是数字模拟混合电路。更应注意在系统设计上防止干扰，而不是单纯依赖器件本身的功能。
[问：智能2000] 该芯片适用网压多少伏（最高？最低？）？直流还是交流？传输距离多远（KM）？适用何种方式？
[答：Peng] the IC it self has no limitation in mains voltage as long as insulation is up to the requirement. It can transmit signal via any pair of wires for up to several hundred meters without the help of relay or external amplifier. The signal is modulated in FSK
[问：heruichun] 在一个通讯区域内,最多可以有多少个ST7538存在,如何进行一对一通讯而不影响其他设备
[答：Peng] ST7538 itself is a very transparent data interface between node to node. The data transmitted by st7538 is broadcasted to the whole network and the reciever has to recognize it with the specific communication protocal between the transmitter and the reciever. and this is decided by the software. So the total amount of 7538 in a network has no limit. But at any moment only one 7538 can transmitt at a given channal to avoid interference.
[主持人：ChinaECNet] 在此回答问题的专家是ST公司的：Peng Chao，Valentino Archetti和Vincenzo Marano。
[主持人：ChinaECNet] 在此回答问题的专家是ST公司的：Peng Chao，Valentino Archetti和Vincenzo Marano。
[问：heruichun] 请问：1、电力线上网猫的速度可以达到14Mbps,本产品与电力猫有何区别；2、在电力猫中网桥与猫必须是在同一个回路中，如通过变压器就不能进行载波通迅，本产品是否也有这样的问题；3、本产品的传输距离可以达到多少，传输的距离与速率之间的关系。谢谢！
[答：Peng] 1, this product is for narrow band appliation. but in principle they are the same. But the modulation techniqueis different .
2 It"s the same. Transformer can attenute the signal significantly.
3 With our built in amplifier, the max distance of transmission can be 300--500 meters. And in theory lower carrier frequency suffer less attenuation for the same distance.
[问：txling216] 请问电力线载波通讯芯片ST7538与专用的FSK调制芯片有什么不同?如果我把它用在非电力线的FSK通讯中可以吗?
[答：Peng] It can be used in any FSK application as long if carrier frequency and bandwidth fit your need.
[问：wy56] 能告知购买的渠道、价格，及如何获得样片吗？最好能提供参考设计，谢谢！
[答：Peng] Please contact our local ST staff or distributors for quotation issue. more information about st7538 can be found on www.st.com including demo board design
[问：joseph.zhou] FSK方案比之PSK或者其他擴頻方案在PLC領域有何優勢?
其數據速率是否還有提高的可能?
[答：Peng] under current regulation in the Europe and the US. FSK can utilize the band better hence tranmitt at higher data rate. It is possible to increase the datarate but not much under the EN regulation for power line communication.
[问：wxgsnake] 能否传输视频信号
[答：Peng] not suitable for video signal given the narrow bandwidth of the device
[问：changhong.liu] 此芯片对于电网所产生的各类干扰是怎样屏蔽的?
[答：Peng] signal coupling transform filter circuit has to be well designed to cope with the interference on the power line.
[主持人：ChinaECNet] 在此回答问题的专家是ST公司的：Peng Chao，Valentino Archetti和Vincenzo Marano。
[问：chengyan] 1）该芯片在专线上是否能用？
2）测试过的最远距离是多少？
3）芯片价格如何？是否能提供测试样片？
[答：Peng] 1 yes,
2 without external amplifier, 300--500 meters
3 please contact local st branch or distributor for quotaion and sample application.
[问：hustei] ST7538能否自身完成比特流的无差错传输（意思就是说，不需要用户来进行差错编码）？
[答：Peng] no, it has to be done by external processor
[问：fx118_1999] 阻抗适配器如何选择？
[答：Peng] LISN? Please follow the standard you wish to comply with. In we built our LISN according to EN.
[问：mitou163] ST7538如何保证保密的安全性？
[答：Peng] It can be done by coding data under transmission in a secure way.
[问：yialong] ST7538的通信效果如何？和晓程、YITRAN等公司的芯片比较有什么优势吗？
[答：Peng] ST7538 is a robust device. And it can transmit data quicker than many other devices.
[问：Dicksion.Lu] 由于7538内部集成了有1W的功放大器,那么请问其是否要比同类芯片的发热要厉害呢?其在高温段的工作性能如何?
[答：Peng] Yes ST7538 can generate heat during transmission. It can perform reliabally up to 85c
[问：yindz] 1.是模拟还是数字的？
2.带宽多少？能否组成小局域网？
3.传输／通讯距离有无限制？
[答：Peng] 1 ST7538 use SPI to communicate with MCU, and the power line interface is analog,
2 from 600bps--4800bps
3 Please refer to some previous answers
[问：qilin315] 该电路的抗干扰能力是否比过去有较大提高？对瞬间的脉冲噪音有什么有效的解决办法？
[答：Peng] Trancient and spikes on the power line can be filtered by some external passive components.
[问：tianjiu] 请问变压器对电力载波通讯的影响如何？谢谢！
[答：Peng] Usally signal can not pass through power transformers.
[问：szxszx] ST7538的供电是否要与电力线隔离？
[答：Peng] not necessarily. but the power line interface must be isolated
[问：liuhuju] 请为电力载波线通讯面对的电力网对载波频率在不同时间段阻抗变化较大和谐波干扰提供建议？liuhuju
[答：Peng] use a peak detector to sample the carrier level. then switch between normal or high sensitivity mode and turning the integrated filter on/off. well designed filter circuit can filter out harmonics efficiently.
design a good error correction function into the communication protocal.
[主持人：ChinaECNet] 各位观众，现在用户提问很踊跃，专家正在逐一回答。请耐心等待您问题的答案，同一问题请不要多次提交。
[问：lsh2813] 7538与电力线之间的藕合滤波有无参考样本?
[答：Peng] yes, please refer to our datasheet and application notes on www.st.com
[问：fangdk] 在住宅小区内的有效通迅距离是多少？该距离是否会随同用户使用家电的情况有所变化？
[答：Peng] several hundred meters. Carrier will be weaker when the load is heavier.
[问：lsh2813] BFSK中的B为何意?
[答：Peng] binary frequency shift keying
[问：dengxy11] 能在35KV以上等级的电缆上传输吗
[答：Peng] it"s not suitable due to the difficulties in isolation and many other aspects.
[问：zhongbx] 能不能跨越电力变压器进行数据传输？
[答：Peng] no without the help of bridges.
[问：fangdk] “更重要的是外围滤波电路的设计和系统的设计......”,但根据本人多年的电力线载波研究，电力线上什么频段的杂波都有，而且还与用户使用负载的时间不同而不同。请问，如何能做到过滤干扰？
[答：Peng] yes there are various kinds of interference on the power line. thus we choose a band pass filter to let only the carrier frequency pass through. But still FSK can not avoid the noice on the carrier frequency. thus it is helpful to switch the carriar frequency when needed
[问：fmfen] 请问是否只能在同相的电力线传输？
[答：Peng] Yes.
[问：tenson] 欧洲的电力载波频段是3-148.6Khz，那我国是否是采用这个标准呢？
[答：Peng] the "standard" in china is not very clear yet, but it is possible to follow Europe standard in the future
[问：tianjiu] 用ST7538组网可以吗？最多可以到多少数量？
[答：Peng] Yes, and the number of st7538 is not a problem. But it"s not possible for more than one to transmitt at the same time on the same channal
[问：shaobo_xu] 该芯片能不能用在电机的监控上？
[答：Peng] Yes it"s possible. there are some applications on the locomotive traction control
[问：wwsstt2001] 请问用的是那种传输协议？
[答：Peng] st7538 is only a data interface. it is not relerant to any specific communication protocal
[问：yinguowang] 此芯片如何适应电网的不断变化的负载特性?
[答：Peng] the device has current and voltage control on the anlog output and auto gain control on the recieved analog input.
[问：ygxmonkey] 在武汉地区有没有branch distributor？联系方式是什么？
[答：Peng] please call 0755-86012283 for distributor information
[问：sh3cie] 1，ST7538是否存在载波检测延时？
2，载波信号指示的的响应需要多少周期？
[答：Peng] 1 yes, 0.5ms or more
2 can be set by the register of st7538
[问：WZCACY] 集成电力线驱动接口如何控制的？
[答：Peng] it"s controlled by st7538 automatically
[问：WZCACY] 如何保证上电复位时间和顺序
[答：Peng] use the internal 5V regulator to power the digital section of 7538 and properly design the grounding, and capacitance and inductance on the 5V output.
[问：小远] 请问此芯片在发送模式时一定要消耗350MA的电流吗
[答：Peng] no, st7538 has current and voltage control on the output amplifier. the level can be set by a resistor.
[问：yinguowang] 利用ST7538的过零检测,使信号在交流过零时传输效果会更好吗?
[答：Peng] Yes it"s possible. also it is a way to adress carrier signal.
[问：zyesyes] 如果线路上存在大功率电阻性负载,信号衰减是否严重?
[答：Peng] yes but the sesitivity of 7538 is very high.
[问：dimin] BFSK全称是什么？
[答：Peng] binary frequency shift keying
[问：sh3cie] ST7538是否能够被检测二个以上收发器同时发送数据时的载波冲突？这种情况下ST7538的输出结果会怎样？
[答：Peng] This will generate error.
[问：shzj527-1] ST7538的滤波是如何实现的？
[答：Peng] inside st7538 there is a 4pole Sallen-Key filter, and it is crucial to design the external filter correctly.
[问：dlp145] st7538的供电如何与电力线隔离
[答：Peng] Transfomer is commonly used for isolation.
[问：loveyes] ST7538的低温适应范围如果，贵公司所作的PLC在低温环境下最低可以工作在多少摄氏度
[答：Peng] -40----+85 不错，谢谢 r166 发表于 2012-7-24 08:37 static/image/common/back.gif
不错，谢谢
最近在做电力线载波设计，发现论坛里这方面可查的资源实在太少了，找到了就补充一些进来，呵呵。
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