| 主题：SI473X 全波段数字收音调谐器系统PCB设计与应用 |
| 在线问答： |
| [主持人：ChinaECNet] |
各位听众（网友），上午好！欢迎参加中电网在线座谈。今天，我们有幸邀请到Silicon Labs公司的专家就“SI473X 全波段数字收音调谐器系统PCB设计与应用”举行在线座谈。在座谈中，您可就您关心的问题与Silicon Labs公司的专家在线进行直接、实时的对话交流。中电网衷心希望通过大家的共同努力，不仅能够增进各位听众（网友）对“SI473X 全波段数字收音调谐器系统PCB设计与应用”的了解和掌握，而且能够为大家事业的发展带来裨益。 |
[2008-10-30 10:15:56] |
| [问：windg] |
您好，我知道一般高频射频线要求是50欧姆，那么请问这个系统在设计PCB时，信号线的设计应该遵循什么原则？有哪些问题需要注意？谢谢！ |
| [答：Jonathan] |
我们芯片的输入阻抗并不是50欧姆，所以RF输入线无须按照阻抗线设计的原则设计成50欧姆阻抗线，但依然要遵循EMC设计的各种原则，如RF走线越短越好，RF走线不得与其他信号线平行走线等。具体的指导细则请参考我们的应用笔记。 |
[2008-10-30 10:28:03] |
| [问：thmjj] |
SI473X 全波段数字收音调谐器有厂家用在显示器上吗?或PCTV一体机上吗? |
| [答：Zhangligang] |
有。 |
[2008-10-30 10:30:04] |
| [问：flyakiteyx] |
请问，全波段数字收音机的本振是如何得到的？ |
| [答：Abhijit] |
LO is generated by dividing down the VCO frequency. Assume that the radio is tuned to frequency X MHz, Intermediate Frequency is constant, lets call it Y MHz. Assume the VCO is running at Z MHz. The LO frequency can be X+Y or X-Y depending on if one is using high or low side injection. If it is X+Y, the divider setting will be Z/(X+Y). |
[2008-10-30 10:31:14] |
| [问：kubeman] |
这个产品上市了嚒？既然是PCB设计与应用 应该是讨论技术，为新产品登陆，拉人气的。 质量一定棒，收音机里面如“SHARP“ 不错，夏普很多产品都做的呢！ 来看过了 谢谢 品牌+质量+价格效应 应能有人气的 嘿嘿 |
| [答：Louis] |
谢谢！ |
[2008-10-30 10:33:01] |
| [问：flyakiteyx] |
对于前端的小信号放大部分有什么经验呢？我使用过MC3362，这个芯片的性能非常好，而且前端的放大做的很好，不知道能从中得到什么建设性的东西？ |
| [答：Jonathan] |
Si4730的AM灵敏度及FM灵敏度已经足够满足一般应用的要求，无须外加电路进行前端放大，只需要根据应用笔记中的设计规则使IC良好工作起来即可，所以设计经验方面主要是要注意RF部分走线的LAYOUT设计及天线本身的匹配问题，细节部分请参考应用笔记。当然对于更高的灵敏度要求，我们也有推荐的外围LNA电路可进一步提高灵敏度。 |
[2008-10-30 10:33:40] |
| [问：胡信汉] |
S1473X芯片的频率覆盖系数是怎么处理的。我们怎样设计出性能更好的收音机（主要是指在频率分段多的情况下）？ |
| [答：Jonathan] |
对于短波，我们并不需要进行频率分段，所以整个波段内的性能是一致的。 |
[2008-10-30 10:35:11] |
| [问：thmjj] |
可以提供整套应用方案吗?联系方式:唐焕明 0755-84710161 深圳市神舟电脑股份有限公司 |
| [答：Jonathan] |
可以的，请联系我们的代理商。 |
[2008-10-30 10:35:56] |
| [问：john_yu] |
tuner时钟信号的处理?
1.tuner自己产生时钟
2.由baseband产生时钟,供tuner
哪种方式好一些? |
| [答：Greg] |
Generally it is better to use the baseband to generate the clock because a crystal and two load caps are required in this case. |
[2008-10-30 10:35:59] |
| [问：肖硕文] |
SI473X IC与传统的相比，在哪些方面改进的比较好？？（比方说外围电路设计） |
| [答：Greg] |
Primary advantages are performance, size, ease of design and total BOM cost. |
[2008-10-30 10:36:53] |
| [问：liguang169] |
请问市场上常见的德生和凯隆的便携机是否采用的便是Silicon Labs公司的Si473x系列芯片？ |
| [答：Zhangligang] |
德生和凯隆的新款都是用的Si473x芯片。 |
[2008-10-30 10:37:17] |
| [问：liguang169] |
德生的一些便携机可以在液晶屏上看到电台以及歌曲的名称，这个功能是Si473x系列芯片具备的功能，还是德生自身附加设计的外部电路？ |
| [答：Jonathan] |
这是RDS接收功能，该功能是Si473X本身具有的功能，无需外加外部电路，这也是Si473X比传统方案先进的地方之一，一般传统方案要加RDS功能，都需要外加RDS解码芯片。 |
[2008-10-30 10:38:00] |
| [问：sunrays] |
作为电子爱好者，我非常喜欢收音机，应该买过有10多台（不同大小，或者有特殊扩展功能等）。很期待了解本次主题所讲的调谐器系统有何可圈可点之处？ |
| [答：Louis] |
Si473x是所谓的DSP收音机，主要指信号进来后经过低中频，然后由DSP来处理。另外针对AM，是对传统AM方案的一个突破，它使得在手持终端如手机上实现AM功能成为可能，同时也无须进行生产校准。 |
[2008-10-30 10:39:35] |
| [问：liguang169] |
对于天线的选择，Si473x系列芯片是否有要求？ |
| [答：Greg] |
Yes. Your options are a ferrite loopstick or airloop. The ferrite loopstick can range in size from a surface mount device suitable for handsets to a large device suitable for table radios. The airloop will be large (15cm x 12xm approx) and suitable for tabletop and very high performance applications. |
[2008-10-30 10:41:06] |
| [问：liguang169] |
Si473x系列芯片在调幅输出与功放输入之间增加低通滤波，对于音质是否会有提升？ |
| [答：Jonathan] |
对音质没有明显的帮助，但在测量方面，或许会对抑制一些可能存在的>20KHz的噪声有一些帮助，而使测量结果变好。 |
[2008-10-30 10:41:15] |
| [主持人：ChinaECNet] |
我们已经进入问答阶段如果听众想重温演讲或内容可以点击下面“回顾演示”重看演讲。 |
[2008-10-30 10:42:05] |
| [问：胡信汉] |
S1473X芯片提供二次调谐电路吗？它的设计方式有几种？ |
| [答：Zhangligang] |
Si473x 是全集成的收音芯片，没有外围电路的设计需要。 |
[2008-10-30 10:43:44] |
| [问：sxj0456] |
pcb设计如何防止啸叫？ |
| [答：Jonathan] |
一般来说产生啸叫并不是由于Si473x部分电路设计不当产生，而是由于音频输出及后级功放部分电路设计问题产生，具体Si473x PCB Layout方面设计注意事项请参考应用笔记AN383 |
[2008-10-30 10:44:01] |
| [问：胡信汉] |
S1473X芯片对于输入信号的最低要求是多少场强？它用什么技术提高对微波信号的分辩能力？ |
| [答：Jonathan] |
灵敏度方面，对于IC， FM 2.2uVemf / 26dB SINAD, AM 25uVemf / 26dB SINAD. 因为Si473X为数字架构，使用DSP进行信号处理的接收机，所以在抗干扰方面比传统的收音机要好15-25dB. |
[2008-10-30 10:48:17] |
| [问：vincent.q.y.xie] |
抗干扰性能:如何避免来自机内的多种干扰?如Class D的;MCU的,开关电源的? |
| [答：Greg] |
Careful layout (including possibly shielding of the tuner), careful routing of traces and frequency planning of switching frequencies (including harmonics) are required. Refer to the presentation slides for examples of these techniques. |
[2008-10-30 10:49:14] |
| [问：gumulaoyi] |
数字收音调谐器相对于以前的模拟调谐器，有何优点和不足？ |
| [答：Louis] |
1. 优点是外围器件少，性能稳定，比如模拟收音机的频偏问题。还有诸如搜台准确假台少等优点。
2。 缺点是功耗稍高（工作时15mA左右） |
[2008-10-30 10:49:42] |
| [问：胡信汉] |
S1473X芯片对电源的纹波系数有什么要求？最低的指标要求是多少？ |
| [答：Jonathan] |
The chip is designed to work with a supply voltage (VA, VD) range of 2.7V to 5.5V with a maximum ripple
of 600mV peak to peak with a 10ms edge rate, 217Hz maximum. As long as the ripple doesn’t violate the
minimum of 2.7V or the maximum of 5.5V it will work as expected. The internal LDO has better than
50dB PSRR for frequencies less than 200kHz. |
[2008-10-30 10:50:31] |
| [问：胡信汉] |
S1473X芯片有多少条脚，它属于现代最先进的集成电路技术产品还是在旧的集成电路技术上变形技术？ |
| [答：Louis] |
20脚。标准CMOS工艺。 |
[2008-10-30 10:50:37] |
| [问：teiliyuan] |
对接收天线的要求有何规定？FM拉杆天线最短长度、AM频段的天线最低要求为何？ |
| [答：Zhangligang] |
Si473x 的高灵敏度意味着FM可以用较短的天线。长度取决于对灵敏度的接受程度。AM一般的传统天线都行，但用我们建议的会更好。 |
[2008-10-30 10:50:43] |
| [问：shaoziyang] |
影响接收灵敏度的因素有哪些？ |
| [答：Abhijit] |
Noise and distortion, noise mostly since distortion would be a negiligible contributor at RF levels at which sensitivity is defined. Noise can be both conducted and radiated some examples are switcher noise, digital noise because of digital signals toggling. |
[2008-10-30 10:51:07] |
| [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。 |
[2008-10-30 10:52:27] |
| [问：albertwang114] |
从耳机接口到芯片的FMI频脚之间的TRACE 的长度和宽度有什么具体的要求? |
| [答：Jonathan] |
这是很重要的一段走线，长度越短越好，宽度没有要求，一般走10mil左右的线，当然，如果PCB走线需要，再窄一些也没有问题。 |
[2008-10-30 10:52:36] |
| [问：胡信汉] |
S1473X芯片的外电路配件有没有特殊的要求，能否用市场上的通用配件生产收音机产品？或者它对于某些外部零件有特殊要求？ |
| [答：Greg] |
The BOM requirement is limited to a bypass capacitor for VDD and dc blocking cap, which are both standard C0G components, and a ferrite loopstick or airloop antenna. Silicon Labs has worked very closely with Jiaxin Dianzi in China to develop high performance antennas for this purpose. |
[2008-10-30 10:56:02] |
| [问：ps.tl] |
请讲一下SI4734 SI4702的时钟晶振接法？ SI4702的17脚是否也为DCLK? |
| [答：Jonathan] |
SI47XX支持两种参考频率提供方式。一种是直接提供一个参考频率到RCLK引脚，另外一种是在RCLK引脚与GPIO3引脚之间接一个晶体，使用IC内部的振荡器提供参考频率。 Si4702的17脚为GPIO3,如果你使用第二种方式，即在这个脚与RCLK引脚之间接上一个晶体。 |
[2008-10-30 10:56:59] |
| [问：sd2620] |
Si473x能集成到移动电话中吗？请问是否已经有实际应用？请专家列举一二。 |
| [答：Greg] |
Yes. Sony Ericsson R300 and R306 and Longcheer X620e are available on the market now and offer very good performance. |
[2008-10-30 10:58:18] |
| [问：liguang169] |
传统的调幅/调频收音机芯片需要手动调校元器件，Si473x系列芯片是否也需要？ |
| [答：Abhijit] |
The Si473x series does not use any components which need manual tuning. The Si473x series integrates the complete tuner function from antenna input to audio output including the AGC controls. |
[2008-10-30 10:59:14] |
| [问：liguang169] |
Si473x系列芯片是否是目前唯一一款将调幅/调频/短波/长波接收能力整合至一块芯片的器件？ |
| [答：Jonathan] |
是的，并且是唯一目前市面上可以看到量产的最终产品的。 |
[2008-10-30 10:59:50] |
| [问：wangpf] |
你好，我想请问，实际使用时的工作电压是否可以支持2节AA电池，以前测试过，在电池电压降低到2.8V以后工作可靠性就很差，所以有些工程师设计成3.6V的锂电池，那请问现在是否能适用于2节AA电池的袖珍收音机场合？ |
| [答：Greg] |
The Si473x are specified and specs are guaranteed to 2.7V. We don"t guarantee voltages below this level, however, the tuner will operate to 2V or below. There are some examples of customer doing this today with products on the market. |
[2008-10-30 11:00:44] |
| [问：sligu] |
请问si473x的前端模拟调理电路部分需要哪些主要器件？ |
| [答：Louis] |
非常少。fm只要一个匹配电感，一个隔直电容。AM如果使用瓷棒天线只要一个电容。 |
[2008-10-30 11:01:15] |
| [问：sd2620] |
我以前使用收音机的时候，有些台总是很模糊，请问Si473x是否能大幅改善这种状况？ |
| [答：Jonathan] |
是的，因为数字架构的473X可以提供更高的灵敏度以解决信号弱的问题，同时它可以提供更好的选择性以解决干扰强的问题。所以会大幅改善客户的收音体验。 |
[2008-10-30 11:01:23] |
| [问：sligu] |
control interface提供哪些参数的设置？配置速率是多少？ |
| [答：Abhijit] |
Both 2-wire and 3-wire options are supported.
For 2-wire control interface maximum clock frequency is 400KHz and for 3-wire control interface maximum clock frequency 2.5MHz. |
[2008-10-30 11:01:42] |
| [问：lcdi] |
灵敏度如果还想更高，可以加高放吗？强信号会不会因此过载而阻塞？ |
| [答：Zhangligang] |
高放加得好可以进一步提高灵敏度，强信号阻塞可以解决，有问题请找我们的工程师帮忙。 |
[2008-10-30 11:02:18] |
| [问：sd2620] |
请问SI473X芯片是否支持此功能：将电台和歌曲名称等信息显示在屏幕上？ |
| [答：Louis] |
Si4731可以，就是需要RDS，sI4731支持RDS。 |
[2008-10-30 11:02:24] |
| [问：hzchem] |
Si473x单颗芯片中是否集成了接收输入信号和输出音频信号的所有功能全部? |
| [答：Zhangligang] |
是的。 |
[2008-10-30 11:02:32] |
| [问：hyb107] |
可以把原理和4735的PCB传到我的邮箱里吗？谢谢！ |
| [答：Louis] |
请留下邮箱。
|
[2008-10-30 11:03:36] |
| [问：busuanzi] |
我设计的si4730会出现死机的情况 |
| [答：Jonathan] |
请联系我们的代理商要求技术支持，一般可能是软件方面的问题。 |
[2008-10-30 11:03:49] |
| [问：lcdi] |
贵公司的芯片音质如何，能达到汽车收音机的水平吗？如果能，那种芯片可以，如何达到，谢谢 |
| [答：Abhijit] |
Silicon Labs has the Si474x family which caters to the automotive radio market. |
[2008-10-30 11:05:04] |
| [问：darren1] |
天线距离周围的铺铜建议要保持多远的距离? |
| [答：Jonathan] |
不同天线（AM/FM/FM短天线）有不同的建议要求，请参考AN383文档。 |
[2008-10-30 11:06:44] |
| [问：spig20] |
各位专家上午好！我们公司在目前的一款产品中设计了FM收音机功能，芯片型号是SI4702，但是，目前存在一些问题，主要是：采用自动搜台时，假台和空台的现象比较严重；通过读RSSI寄存器，发现96.0MHz的信号强度非常强，事实上，本地区（安徽合肥）是没有这个台的.FM接收天线采用耳机公共端接线，敬请各位专家能够帮忙分析一下这个原因吗？ |
| [答：Louis] |
1。假台问题：你现在三个搜索门限你设为多少？同时你可以再加多一个判断-AFCRAIL
2。96MHz可能是USB谐波，你是啥产品？ |
[2008-10-30 11:07:47] |
| [问：sligu] |
请问一般采用si473x设计的收音系统的pcb是几层板？电源层和地层怎么分布？ |
| [答：Jonathan] |
单面板到六层板都可以，不过我们建议两层板及以上，我们对电源层和地层的分布没有特别要求，最好是地层可以在IC所放元件层的下一层。 |
[2008-10-30 11:08:51] |
| [问：liushangqing] |
在PCM设计中，计算信号特性阻抗等参数时，若人工去计算很烦琐，且很容易出错，有无此类设计工具软件？谢谢！ |
| [答：Jonathan] |
我们IC无需进行阻抗线设计。所以无需进行特别计算。 |
[2008-10-30 11:09:56] |
| [问：lcdi] |
作为业余开发者，网站上没有详细的资料，请问4734有没有省电模式？ |
| [答：Louis] |
Si4734 power down以后功耗是微安级的，应该是省电模式。 |
[2008-10-30 11:10:05] |
| [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。 |
[2008-10-30 11:11:54] |
| [问：liushangqing] |
如何选择PCB板材?如何避免高速数据传输对周围模拟小信号的高频干扰,有没有一些设计的基本思路? 谢谢 |
| [答：Jonathan] |
SI473X对PCB板材没有特殊要求。
基本的设计思路是1.如果可以使用地层对数据线进行屏蔽，则屏蔽。2.在数据线上串联电阻，且将该电阻靠近控制器端。3.在数据线上并联电容，但要注意不影响软件时序。4.走线上数据线距离天线尽量远。 |
[2008-10-30 11:12:11] |
| [问：flyakiteyx] |
啸叫干扰和散弹噪声有什么好的方法可以减小吗？ |
| [答：Jonathan] |
请参见前面对啸叫干扰问题的回答 |
[2008-10-30 11:12:54] |
| [问：liushangqing] |
一些系统中经常有A/D，问：要提高抗干扰性，除了模拟地和数字地分开只在电源一点连接，加粗地线和电源线外，希望专家给一些好的意见和建议！ |
| [答：Zhangligang] |
我们的A/D是集成的。不需要有类似考虑。 |
[2008-10-30 11:12:56] |
| [问：darren1] |
FM 天线的长度和走线宽度可以如何计算?或是要啥要求和限制? |
| [答：Jonathan] |
请参见前面的回答或参考AN383文档 |
[2008-10-30 11:13:12] |
| [问：karryc] |
473X系列 rev.0.5 datasheet中注明可用于car radios,
在rev.1.0 中将car radios应用去掉了，为什么？
SI473X系列能应用于car radios吗? 高速（例如120km/h）情况下表现如何？ |
| [答：Greg] |
The Si474x family of products was introduced shortly after this datasheet version. The Si474x family of products are a better solution of automotive applications due to single antenna (automotive whip) RF input, noise blankers (AM/FM) for engine noise supression, and high-cut features for multipath mitigation.
At 120 km/h multipath is more likely (especially near buildings and other structures) and sound quality will be improved with mulitpath mitigation. |
[2008-10-30 11:14:08] |
| [问：xwlyy] |
请问在芯片应用中针对不同类型电池，电源电路有什么需要特别注意的。 |
| [答：Greg] |
No special consideration is needed. Alkaline or lithium ion are the most common batteries for portable devices. Care should be taken not to exceed the the minimum power supply rise time of 10uS (see datasheet) in the event that the supplies are connected directly to the battery. Care should also be taken to ensure that switching noise is suppressed if there is a charger in circuit. The PSRR of the tuner is very good, however, other types of coupling can be an issue if the power supply is not clean. |
[2008-10-30 11:18:30] |
| [问：liguang169] |
Si473x系列芯片作为首款高度集成的调幅/调频收音机芯片，它的音质效果如何？ |
| [答：Abhijit] |
Typical values for FM sensitivity is 2.2uVEMF and for AM is 25uVEMF which are comparable to the best in the market. It has features like soft mute, stereo mono blend, adaptive noise suppression, adjustable channel filters which makes the audio quality top notch.
|
[2008-10-30 11:18:40] |
| [问：cdwangxiuying] |
在PCB设计阶段，排除辐射噪声非常关键，除了用示波器看到信号波形外，有没有设备看到辐射的＂图形＂以及电路板上的回流呢？ |
| [答：Jonathan] |
可以用频谱仪看到干扰信号的大致频率及频谱状况，同时可以用音频分析仪看到干扰信号产生的音频频谱的状况来辅助分析。 |
[2008-10-30 11:20:06] |
| [问：sxj0456] |
系统板和原件的减少，如何控制接收灵敏度和系统稳定性？ |
| [答：Greg] |
RX sensitivity for AM/FM is maximized for both bands by following component selection and layout guidelines found in application note AN383. Stability is guaranteed. |
[2008-10-30 11:21:15] |
| [问：liushangqing] |
在高速PCB设计中，信号层的空白区域可以敷铜，那么多个信号层的敷铜是都接地好呢，还是一半接地，一半接电源好呢？ |
| [答：Abhijit] |
Any floating copper should be tied to ground. Although supply is considered to be AC ground it is still not hard ground since the LDO or the switcher has an output impedance. |
[2008-10-30 11:22:27] |
| [问：lcdi] |
据说一些面世的收音机听起来有些背景噪音，这个问题有解决办法吗？ |
| [答：Greg] |
Standard methods for reducing noise in the AM band is enable softmute or limit AVC gain and in the FM band by enabling softmute. The Si473x AM/FM tuners offer these features. |
[2008-10-30 11:23:24] |
| [问：cdwangxiuying] |
一个系统往往分成若干个PCB，有电源、接口、主板等，各板之间的地线往往各有互连，导致形成许许多多的环路，产生诸如低频环路噪声，不知这个问题如何解决？ |
| [答：Jonathan] |
改善接地状况是最直接的方法。如把放置SI473X的PCB的地直接连到主板的大地上。或者是检查是哪块系统造成的干扰，改善该系统的接地状况。 |
[2008-10-30 11:23:25] |
| [问：bowei181] |
请问输出端能直接驱动外置扬声器吗？ |
| [答：Greg] |
The LOUT and ROUT pins cannot drive external speakers directly. Maximum loading is limited to 10kohm || 50pF. To drive external speakers an amplifier is required. |
[2008-10-30 11:24:19] |
| [问：albertwang114] |
如果FM的天线真的走不了表面,要穿过好多层,那需要有什么好的办法? |
| [答：Jonathan] |
走里层的时候要注意尽量短，且不要在好几个内层走线，尽量保持在同一个内层走线，减少过孔数量，同时要注意避免其他走线对天线走线的干扰。 |
[2008-10-30 11:24:55] |
| [问：sxj0456] |
S1473X芯片的接收性能与MC3363比较有哪些优点？ |
| [答：Jonathan] |
我们没有针对MC3363进行特别的比较，但从市面上现有产品来看，我们的灵敏度及选择性指标都是相当高的，而且无须外围RF放大电路。 |
[2008-10-30 11:26:17] |
| [问：tecobest] |
对于FM接收，软件上可以采取那些降低干扰的措施 |
| [答：Louis] |
对于干扰主要是硬件啦，软件可以设置几个搜索门限防止假台， 或者设置BLEND使得信号差时自动变成单声道。 |
[2008-10-30 11:26:18] |
| [问：powerbird] |
请问：SI4730/31 在行驶速度达到100KM/H 效果如何，有多大的影响？ |
| [答：Abhijit] |
If by speed its being implied if the Si473x family can be used for automotive radio systems or not, Silicon labs has the Si474x family which caters to the automotive radio market.
|
[2008-10-30 11:28:10] |
| [问：powerbird] |
SI473X 锁不住电台，或偏台，有哪些原因或因素导致？ |
| [答：Greg] |
Possible reasons for false stops or missing channels during seek are corrupted reference clock (RCLK) (explains both cases), incorrect RSSI and/or SNR thresholds (explains either case, but not both simultaneously), system noise (can explain missed stations due to reduction in SNR)or system spurs (can explain false stops).
If the tuner stops on the low side or high side of desired channels consistently, it is most likely due to an inaccurate reference clock (RCLK) frequency. |
[2008-10-30 11:29:08] |
| [问：powerbird] |
影响自动搜台的因素有哪些？ |
| [答：Abhijit] |
SNR and RSSI.
Both these can be programmed by the users. |
[2008-10-30 11:29:12] |
| [问：flyakiteyx] |
数字收音机有哪些部分是模拟的呢？比如，本振？功放？MIXER? |
| [答：Greg] |
All parts of the tuner are analog up to and including the I and Q channel ADCs. The digital portion of the tuner includes the DSP engine. |
[2008-10-30 11:30:59] |
| [问：licki518] |
SI47XX在其适用的频段上是否能够保证所有频率信号的准确接收，也是就说是否在某些频带上接收灵敏度不行？ |
| [答：Jonathan] |
在规格书规定的频段内IC完全可以达到规格书上标称的灵敏度，如果有问题，请联系我们要求技术支持。 |
[2008-10-30 11:31:27] |
| [问：woshijinmi] |
有些mp3播放器内置有FM调谐器，是否使用的就是Si473x芯片或者类似的芯片？ |
| [答：Louis] |
是的。 |
[2008-10-30 11:31:45] |
| [问：bowei181] |
能否提供Si4731的完整应用方案？到哪里能够下载？ |
| [答：Jonathan] |
可以，请联系我们的代理商。 |
[2008-10-30 11:31:53] |
| [问：licki518] |
我也需要4735的工作原理和4735的PCB，邮箱是：cyzx1@mail.nedu.edu.cn
谢谢 |
| [答：Jonathan] |
请联系我们的代理商，谢谢！ |
[2008-10-30 11:32:51] |
| [问：hyb107] |
请把原理图和PCB设计发到我的邮箱里,我的hyb107@163.com |
| [答：Jonathan] |
请与我们的代理商联系，谢谢！ |
[2008-10-30 11:34:00] |
| [问：gumulaoyi] |
长久以前的心愿：能有一个全波段收音机，现在有了SI473X芯片，愿望终于能实现了！我想请教：这种全波段收音机，需要配备几个SI473X芯片，体积是否会很大？ |
| [答：Zhangligang] |
您的愿望已经有人实现了。只需一颗芯片，体积可以很小。 |
[2008-10-30 11:34:49] |
| [问：tecobest] |
自动搜索电台的时候，根据读回的RSQ判断电台是否有效会有很多误判，而且真正的电台还会被漏掉，有什么方法可以改进 |
| [答：Abhijit] |
Seek uses the programmed RSSI and the SNR thresholds for detecting the station to be valid or not. These thresholds can be programmed by the customer. If these thresholds are programmed too low then one can have false stops, if they are programmed too high will result in missing stations. |
[2008-10-30 11:35:37] |
| [问：xiaoqf_hz] |
请问如果这颗芯片用于手机中，对于AM和短波的天线如何设计？ |
| [答：Greg] |
General requirements are careful placement of the ferrite loopstick and tuner away from noise sources such as the baseband, PA, LCD, switchers and memory; shielding system components to minimize radiation or susceptibility, disabling or reducing intensity of the LCD during playback; and keeping the antenna away from ground and shielding. |
[2008-10-30 11:36:36] |
| [问：liushangqing] |
评估PCB近场辐射干扰的测量方法？为增强产品的抗干扰性，有没有一种能优化所有电路和元器件的解决方案？ |
| [答：Jonathan] |
对于FM/AM收音机设计来说，评估PCB近场辐射干扰目前还没有一种非常准确，有效的定量测试方法。现在一般我们使用频谱仪测量，其他接收机测量及分析干扰信号音频频谱等实验手段来定位解决辐射干扰问题。辐射干扰问题有较强的个体性，还没有一种统一的规则和方法能直接解决所有辐射干扰问题，需要具体问题具体分析 |
[2008-10-30 11:38:32] |
| [问：huangfeihong88] |
你好！我想问一下，在使用该芯片时，对PCG板有要求吗？ |
| [答：Jonathan] |
对PCB板没有要求 |
[2008-10-30 11:40:36] |
| [问：bowei181] |
能否提供一下si4735的应用原理图及pcb图。我的邮箱：bowei181@tom.com.请问si4735大概多少钱。我想自己制作。 |
| [答：Jonathan] |
请联系我们的代理商，谢谢！ |
[2008-10-30 11:40:50] |
| [问：cdwangxiuying] |
如何解决高速信号的手工布线和自动布线之间的矛盾？ |
| [答：Abhijit] |
All the high speed signals should be routed manually. Care should be taken that they are routed far away from the sensitive portions of the circuitry. Since the Si473x series has really good sensitivity numbers ( FM sensitivity 2.2uVEMF ) any noise coupling from the high speed signals can degrade that number.
Care should be taken that the high speed signals are not routed parallel to the sensitive portions also since in that scenario you will get maximum crosstalk. Another thing to consider is to put ground vias around the high speed traces to limit electric field crosstalk to neighboring traces.
Auto routing does not take all this into consideration. |
[2008-10-30 11:41:06] |
| [问：licki518] |
采用数字调谐器和传统的模拟调谐器相比，对电池的要求是否提高，如果采用传统的5号电池，能用多久？ |
| [答：Greg] |
There are no special requirements for the battery. The Si473x are specified and specs are guaranteed to 2.7V. We don"t guarantee voltages below this level, however, the tuner will operate to 2V or below. There are some examples of customer doing this today with products on the market. The majority of the current consumption in a radio is from the audio amplifier, not the tuner. Users might expect 8-20 hours depending on their design. |
[2008-10-30 11:41:31] |
| [问：cdwangxiuying] |
请教专家，什么叫做容性串扰和感性串扰？分别产生的原理以及对信号产生的影响如何？ |
| [答：Zhangligang] |
请参见前面问题的回答。 |
[2008-10-30 11:42:59] |
| [问：lcdi] |
si473x灵敏度还有办法提高吗？ |
| [答：Greg] |
Improving sensitivity can be best done by increasing the antenna size, minimizing system noise and spurs and omptimizing layout and routing. |
[2008-10-30 11:44:16] |
| [问：老良] |
请问老师，SI473X 全波段数字收音调谐器系统PCB设计主要要注意什么？哪些参数最关键？ |
| [答：Jonathan] |
请参考应用笔记AN383，里面有详细的PCB设计注意事项，一般来说天线部分的走线设计及接地的设计最为重要。 |
[2008-10-30 11:45:17] |
| [问：PETERZHOU] |
有无详细的SI473X 全波段数字收音调谐器系统应用资料(中文版)?
谢谢 |
| [答：Jonathan] |
目前应用资料中编程指南及演示板使用指南有中文版，其他资料皆为英文版 |
[2008-10-30 11:47:03] |
| [问：胡信汉] |
S1473X芯片的外部电路复杂吗？厂家能提供多少种可供参考的外部电路接线图？ |
| [答：Zhangligang] |
Si473x has the simplest applications circuit among all radio ICs. We can help you design the radio that best meet your requirement. |
[2008-10-30 11:47:18] |
| [问：ps.tl] |
请详细介绍一下Digitsl Audio Output的应用，另外那些芯片支持DOUT，谢谢! |
| [答：Greg] |
The digital audio interface is an I2S slave that supports I2S and left justified modes with sample rates between 32 kHz and 44 kHz. The Si4731/35/37/39 support DOUT. |
[2008-10-30 11:49:08] |
| [主持人：ChinaECNet] |
所有问题均已提交给Silicon Labs公司的专家。座谈期间未回答的问题，Silicon Labs公司专家也会逐一回答，并在中电网上公布，请大家注意收看。 |
[2008-10-30 11:49:24] |
| [问：lcdi] |
想要使用si473x，详细的文档资料从哪里获得？ |
| [答：Louis] |
对于Si4730/1可以留下email我们可以给你的
|
[2008-10-30 11:49:50] |
| [问：sjsmailbox2005] |
请问PCB的布线与蓝牙地址码排放有何特别要注意的地方？ |
| [答：Jonathan] |
请参考AN383关于PCB布局及走线部分内容，一般说来，子要遵循AN383中的走线规则，4730与蓝牙芯片不会互相干扰，市面上已有在蓝牙耳机中应用我们IC的实际产品。 |
[2008-10-30 11:50:19] |
| [问：liushangqing] |
请教专家，什么叫做容性串扰和感性串扰？分别产生的原理以及对信号产生的影响如何？我们在设计高速PCB时又怎样来减小这些串扰？应该注意那些问题？ |
| [答：Abhijit] |
Capacitive Inteference:
A trace running on the top layer. Another trace parallel to it running on the bottom layer with a dielectric between them. Since they form a parallel plate capacitor so the signals from one will intefere with the other. this is an example of electric field coupling. This is the reason it is recommended that traces on adjacent layers be perpendicular to each other.
Two traces running parallal to each other carrying current in the same direction on the same layer: This is a typical case of inductive coupling. There will be capacitive coupling too in this case because of fringing electric fields but that it minimum and can be even further minimized by placing grounding vias around the traces. An analogy in this case can be why it is recommended to put inductors which are close to each other in such a way that the mutual inductance between them is negligible. Place them perpendicular to each other. |
[2008-10-30 11:50:36] |
| [问：wyq30118] |
Could you provide relative docments for me,my email is wyq30118@sohu.com |
| [答：Louis] |
Which CHIP?
|
[2008-10-30 11:52:42] |
| [问：honest581] |
传统的收音机中波需要磁棒天线，请问SI473X还需要吗，有了那些改进？ |
| [答：Greg] |
The Si473x requires a ferrite or airloop antenna. Silicon Labs has worked with antenna manufacterers to reduce the size of the ferrite loopstick such that it is now available in a surface mount device 6mm x 4mm x 26mm and suitable for handsets. The Sony Ericsson R300 and R306 are shipping handsets that offer excellent performance using these small ferrites. |
[2008-10-30 11:53:00] |
| [主持人：ChinaECNet] |
由于时间关系，本次中电网“在线座谈”马上就要结束了。虽然各位听众（网友）已与Silicon Labs公司的专家讨论了许多问题，但是还有许多提问没有来得及进行交流。本次在线座谈结束后，中电网将请Silicon Labs公司的专家继续答复所有的来自各位听众（网友）的提问，然后整理上载到中电网网站上，以便大家查阅。 |
[2008-10-30 11:53:25] |
| [问：mentorfar] |
请问SI4734能否在手机上实现？天线设计该注意哪些问题？有哪些建议？ |
| [答：Greg] |
See previous two responses on antenna and layout recommendations. |
[2008-10-30 11:53:38] |
| [问：zxh006] |
请问,想要生产完整的收音机,除了S1473X芯片,还需要些什么器件? |
| [答：Zhangligang] |
天线，简单功能的MCU和攻放。还可以加入显示和按键。 |
[2008-10-30 11:54:25] |
| [问：liyanhua] |
SI473X 全波段数字收音调谐器能实现在线编程么？ |
| [答：Louis] |
请问你说的在线编程是指什么？ |
[2008-10-30 11:54:48] |
| [问：liyanhua] |
请问SI473X 全波段数字收音调谐器的频率范围是多少？ |
| [答：Abhijit] |
Si3736/37/38/39
NOAA weather band support (162.4–162.55 MHz)
FM band support(76–108 MHz)
AM band support(520–1710 kHz)(Si4736/37 only)
Si4734/35
FM band support(64–108 MHz)
AM band support(520–1710 kHz)
SW band support (2.3–21.85 MHz)
LW band support (153–279 KHz) |
[2008-10-30 11:54:51] |
| [问：woshijinmi] |
目前收音机制造商德生和凯隆都开发成功了DSP收音机,请问DSP收音机究竟是怎么回事？ |
| [答：Greg] |
DSP radio means channel filtering, demodulation, stereo processing and other audio processing is done by an internal digital signal processor. Traditional solutions use analog blocks for these functions. |
[2008-10-30 11:55:31] |
| [问：karryc] |
在4740/41的datasheet中看到oem/after market car audio的应用，但在broadcast radio roadmap中仅注明4740/41为high performance,4750/51才是automotive performance,哪一个才更适合car audio使用，4750/51何时可提供评估？ |
| [答：Greg] |
Please contact a Silicon labs representative directly to discuss the Si475x products. |
[2008-10-30 11:56:52] |
| [主持人：ChinaECNet] |
在此，中电网特别感谢给予本次中电网在线座谈巨大支持的Silicon Labs公司，特别感谢专门在线回答各位听众（网友）提问的Silicon Labs公司的各位专家们，特别感谢各位听众（网友）积极热情的参与。 |
[2008-10-30 11:57:33] |
| [问：woshijinmi] |
我感觉手机或者Mp3内置的Si473x性能，与专业的收音机相比，受天线等的限制，其性能没有完全发挥出来，请问专家是这样的吗？ |
| [答：Jonathan] |
在手机中或是MP3中内置AM/FM收音，本身就面临着很多挑战，如，小空间，小天线，强干扰等，所以基于473X的很不错的指标，才可以成功设计出真正市场认可的产品。如果没有这些限制，性能可以好很多。所以性能和体积及便携性，永远都是一个取折中点的问题。 |
[2008-10-30 11:58:04] |
| [问：cdwangxiuying] |
在高速PCB设计时为了防止反射就要考虑阻抗匹配，但由于PCB的加工工艺限制了阻抗的连续性而仿真又仿不到，在原理图的设计时怎样来考虑这个问题？ |
| [答：Jonathan] |
在原理图设计的时候473X不需要特别考虑这个问题，只需要在RF前端加上合适的电感来保证整个前端电路的谐振即可。 |
[2008-10-30 11:59:05] |
| [问：liushangqing] |
您好：我看到很多SDRAM的数据、地址总线上都串接了小电阻（10欧姆到100欧姆），这样做的主要目的是什么？串接的电阻阻值应该怎么来确定？ |
| [答：Greg] |
These are used to minimize the effect of system noise on the tuner. Generally these are not needed, but should be considered as an option. If system noise is large and becomes an issue, selection should be made such that signal rise and fall times are as slow as possible while still meeting timing requirements published in the datasheet. |
[2008-10-30 11:59:12] |
| [问：gumulaoyi] |
Si4731集成度高了，优点是很明显的，但我有个担心的问题：就是维修起来，会不会很麻烦？ |
| [答：Louis] |
实际上坏的概率很小的。如果真是IC坏了那只能换了。 |
[2008-10-30 11:59:40] |
| [问：liushangqing] |
在做AGND和DGND的分割时，隔离槽的宽度多少为合适？8mil是否足够（falltime＝3ns）？ |
| [答：Greg] |
Typically AGND and DGND should be combined. |
[2008-10-30 11:59:49] |
| [问：baipinping] |
AM 需要使用磁棒天线吗？ 短波和长波对于天线有什么特别要求 |
| [答：Zhangligang] |
需要。磁棒天线目前还是接受AM的最佳选择。短波和长波要求不同的电感值。 |
[2008-10-30 12:00:03] |
| [问：cdwangxiuying] |
在高速PCB设计时我们使用的软件都只不过是对设置好的EMC、EMI规则进行检查，而设计者应该从那些方面去考虑EMC、EMI的规则？怎样设置规则？ |
| [答：Jonathan] |
关于PCB设计在EMC，EMI设计方面的注意事项，请参考前面问题的回答或应用文档AN383. |
[2008-10-30 12:00:10] |
| [问：liyanhua] |
请问接收灵敏度和系统稳定性如何？应采取哪些措施提灵敏度和稳定性呢？ |
| [答：Greg] |
Sensitivity is 38uVEMF and stability is guaranteed. See previous response on techniques to improve sensitivity. |
[2008-10-30 12:00:43] |
| [问：zmeng] |
我们是做数字IC的,请问你们的S1473x芯片采用了标准CMOS 0.13um或0.09um工艺? |
| [答：Greg] |
This is confidential. |
[2008-10-30 12:01:03] |
| [问：cdwangxiuying] |
在PCB设计中，退耦电容应该用什么材料的电容性价比最佳？若使用钽电容或陶瓷电容谁的接受效果最好？ |
| [答：Greg] |
Ceramic C0G are best for bypass and RX matching. |
[2008-10-30 12:01:38] |
| [问：sjsmailbox2005] |
请问FM接收时，从软件方面可以采取那些降低干扰的措施 ? |
| [答：Louis] |
软件方面办法不多，主要可以设置一些搜索门限防止假台。但固件中有DSP的一些处理方法。 |
[2008-10-30 12:01:40] |
| [主持人：ChinaECNet] |
祝大家事业有成、生活愉快！欢迎多提宝贵意见，欢迎关注中电网，下次再见。 |
[2008-10-30 12:02:00] |
| [问：baipinping] |
473x现在是主要用于哪个领域？便携式收音机还是手机等？ 有客户开始在手机上使用吗 |
| [答：Greg] |
Both. Sony Ericsson R300, R306 are examples. |
[2008-10-30 12:02:14] |
| [问：nxling] |
S1473X芯片用什么技术提高对微波信号的分辩能力？ |
| [答：Greg] |
DSP processing and advanced AGC and AFC algorithms. |
[2008-10-30 12:02:58] |
| [问：guoshiqiu] |
该调谐器在PCB设计中是否要注意什么?既就是说该调谐器能够承受多少KV静电? |
| [答：Jonathan] |
请参考前面问题的回答及AN383应用文档，对于ESD，473X满足2KV工业标准，一般说来，按照AN383推荐的原理图及LAYOUT注意点进行设计，可以满足最终产品的ESD要求，如4K接触/8K空气。如果需要更好的ESD性能，可以在外部再加上一些ESD保护器件或电路。 |
[2008-10-30 12:05:56] |
| [问：sheldon] |
在全波段数字收音调谐器系统的PCB设计如何控制电磁干扰比如噪声和串扰？ |
| [答：Abhijit] |
Noise and EMI can be suppressed by following the layout guidelines. High speed traces should be kept far away from the sensitive portions ie the AM and the FM front end. Supply should be properly coupled using bypass capacitors. All teh digital traces should be routed on the inner layers. Inteference from high speed digital signals can be controlled by controlling the amplitude and the edge rates |
[2008-10-30 12:06:50] |
| [问：liushangqing] |
在高密度印制板上通过软件自动产生测试点一般情况下能满足大批量生产的测试要求吗?添加测试点会不会影响高速信号的质量？ |
| [答：Jonathan] |
可以的，只要测试点添加得当，不会影响信号质量，已有大批量生产的成功经验。 |
[2008-10-30 12:07:25] |
| [问：liyanhua] |
高速信号PCB布线时需要特别注意什么？ |
| [答：Jonathan] |
请参考前面问题的回答及AN383文档。 |
[2008-10-30 12:08:04] |
| [问：albertwang114] |
如果要过孔穿过多层,那加的电感的位置是否必须要靠近FMI?还是靠近耳机接口? |
| [答：Jonathan] |
电感的位置应靠近耳机接口。 |
[2008-10-30 12:08:37] |
| [问：luoqinghua] |
全波段调谐系统的PCB设计都需要主要哪些问题？ |
| [答：Abhijit] |
1) High speed traces should be kept far away from the sensitive portions ie the AM, FM and SW front end.
2)Grounding vias should be put around high speed traces to prevent electric field inteference to neighbouring traces.
3)Supply should be properly de-coupled using bypass capacitors.
4)All the digital traces if possible should be routed on the inner layers.
5)Inteference from high speed digital signals can be controlled by controlling the amplitude and the edge rates as long as they satisy the timing requirements. |
[2008-10-30 12:11:21] |
| [问：cdwangxiuying] |
在高速设计中，如何解决信号的完整性问题？谢谢 |
| [答：Jonathan] |
该问题是一个比较大的问题，而且最好是针对具体项目与设计来谈，请联系我们如果您在设计中遇到了信号完整性问题。 |
[2008-10-30 12:13:17] |
| [问：胡信汉] |
S1473X能用波峰焊工艺生产产品吗？它本身是采用的什么工艺生产的？在我们使用它做产品的生产过程中对工具的接地有多高的要求？ |
| [答：Jonathan] |
不能使用波峰焊进行生产，因为IC封装为QFN。
对生产工具的接地没有特殊要求，请按照正常生产防静电流程处理。 |
[2008-10-30 12:14:17] |
| [问：cdwangxiuying] |
我们在设计PCB时，将CPU的16位数据和24位地址总线用一个扩展接口引出，以期望能扩展多个其它外部设备。总线频率最高可达40MHz。我们希望使用比较通用的连接器，因此打算采用PC104模块上所使用的64pin长引脚连接器，引脚数量和扩展功能都能满足。
请问专家：采用此连接器是否会制约总线的频率？ |
| [答：Jonathan] |
473X的控制方式十分简单，对于473X的控制，最少只需要3个GPIO口，没有特别的通信频率要求。 |
[2008-10-30 12:15:27] |
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