Not an expert...I dealt with this audio analog stuff long time ago. Basically I'd follow these steps to debug the noise issue: 1. first and foremost, check the whole grounding scheme and quality to make sure the following: a. minimize the digital noise coupled onto analog ground, esp. the ground for the frontend analog amplify. b. minimize the coupling from the output of analog signal to input via the common ground path. 2. feed a clean power supply to analog circuit. 3. the noise floor of the amplifiers. 4. sufficient ampl/phase margins to stay within stable region. 5. minimize xtalk from digital signal, as well as other analog signals. Clock signal often is the culprit that causes a low SNR. 6. minimize mode conversion if the analog signal is differential. 7. check if there is EMI pickups by heatsink, sheet metal, etc. These are what I can think of by now.. Best Regards, Sherman Chen Signal Integrity EMC Global Hardware Engineering Tel: +86 21 60951100-3329 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Saravanan Chml Sent: Wednesday, September 10, 2014 9:18 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Improving SNR in Audio signals-PCB Hi Experts, Can you please advise me about improving SNR (Signal to Noise Ratio) in PCB. I googled it and couldn't find any documents for this. Kindly direct me towards right direction. The frequncy of audio signals that i am dealing is about 1.28MHz only. Thanks & Regards K.Saravanan ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu