标题: MIC到家后怎么办？ [打印本页] 作者: hb-wu 时间: 2003-7-2 15:46 标题: MIC到家后怎么办？ 怎么安置那个小MIC大家有什么想法？是弄根筷子顶上就行了？谁能画画图？谁能代加工？ 作者: 电子管收音机 时间: 2003-7-2 16:09 标题: MIC到家后怎么办？ 对！这个事情我也一直在思考，该如何安置那颗黄豆豆呢？来个圆管把MIC塞进去，外表再来装修一下，那MIC怎样接线才是最好的？放大电路选用哪个是最为合适.........?作者: 电子管收音机 时间: 2003-7-2 16:13 标题: MIC到家后怎么办？ 还是用回这个好呢？作者: 电子管收音机 时间: 2003-7-2 16:14 标题: MIC到家后怎么办？ 来个管子把它顶起来？作者: janorwa 时间: 2003-7-2 17:54 标题: MIC到家后怎么办？ 作个固定架，把他安装到一个小型架子上 我想这样比较好 不容易弄坏 也能很好的固定作者: liyusheng 时间: 2003-7-2 18:35 标题: MIC到家后怎么办？ 电子管收音机 兄，还有没有什么mic放大器的电路，多放一些，放大倍数，素质高一些的。我测量的时候用50cm的距离测量，软件实际收到的信号已经很弱了。至于mic往哪里放？我的是用电脑上用的mic，去掉原来的头，用热缩管把mic和塑料管（跟下图的管子差不多）紧在一起。作者: ljxdw21 时间: 2003-7-2 19:14 标题: MIC到家后怎么办？ 看看mic的大小！！作者: ljxdw21 时间: 2003-7-2 19:16 标题: MIC到家后怎么办？ 看看连线！！作者: ljxdw21 时间: 2003-7-2 19:22 标题: MIC到家后怎么办？ This is a simple microphone preamplifier circuit which you can use between your microphone and stereo amplifier. This circuit amplifier microphone suitable for use with normal home stereo amplifier line/CD/aux/tape inputs. This microphone preamplifier can take both dynamic and electret microphone inputs (preamplifier provides power foe electret microphone elements). The idea of this circuit is to keep the design as simple as possible to be easy to build. That was my goal when I needed a simple external microphone preamplifier for my mixer. The performance of the circuit is nothing superior but can be used with many not so serious projects.
The circuit is a simple one transistor amplifier with amplification of about 30-40 dB (depends on transitor, temperature and voltage). The dynamic mic input is just a simple one transistor amplifier circuit with nothing special in it. LED D1 is in the circuit to show that the circuit operates. The voltage drop caused by LED (around 1.8V for RED led) has been taten in account when designing the amplifier circuit built around Q1. Resistor R4 and capacitor C5 make a filter to filter out possible noise from battery or other power source which is used to feed this circuit. Capacitors C1, C2 and C3 are used to block the DC bias on Q1 base to flow out of microphone input to microphone (the polarity of all capactors is straigh line = + and curved line = -).
Electret microphone input has a resistor R1 fo feeding current through electret microphone capsule when it is connected to the electret microphone input. Electret microphone needs some current (about 1 mA) flowing through it to operate, because there is a small amplifier circuit inside the microphone capsule. This circuit is suitable for all typical cheap electret capsules which available from any electronic component shop. Because electret microphones have higher signal level output, it is quite easy to overdrive the amplifier when you shout to electret microphone. 作者: ljxdw21 时间: 2003-7-2 19:23 标题: MIC到家后怎么办？ The circuit is bet to build to a small metal box like in the picture above. Put the 9V battery inside the case too. Battery power and metal box keep external noise and interference sources away. I used standard 6.3 mm jack for dynamic microphone and 3.5 mm mono jack for electret micrphone both installed to from, panel of the metal box. The LED and power switches are also installed to front panel. 作者: ljxdw21 时间: 2003-7-2 19:25 标题: MIC到家后怎么办？ Measured specifications from protype
Frequency response: 20 Hz to 20 kHz +-1dB
Noise level (A-weighted): -85 dBm
Amplification: 35 dB
Because of the simplicity of the design the distortion performance is not very good. At signal levels typically used by electret microphones the distortion is about 2-3%. With dynamic microphones the distortion level is lower (not measured). Here is the frequency response as measured by LoudSpeaker LAB software DEMO version with Sound Blaster 16 PNP card:
The bass frequency attenuation is caused by the microphone preamplifier circuit. The high end attenuation is caused by Sound Blaster 16 card. As seen in the measured performance, the microphone preamplifier is suitable for speaker measurements made using suitable measurement software and sound card. Using this preamplifier connected to line level input the problems caused by poor microphone preamplifier in many sound cards can be avoided. 作者: Ajconnie 时间: 2003-7-2 19:36 标题: MIC到家后怎么办？ 还有没有简单的、适合me这个初哥做的电路？作者: hb-wu 时间: 2003-7-6 08:46 标题: MIC到家后怎么办？ 大家比较一下关于MIC应用的两种方案：
1，模拟型：MIC-→IC话放-→PC声卡-→频谱分析
2，数字型：MIC-→ADC-→USB/232接口-→PC声卡DG接口/程序接口-→频谱分析
哪种方案精度高些？成本低些？可行性大些？......？ 作者: liyusheng 时间: 2003-7-6 10:21 标题: MIC到家后怎么办？