A plurality of Goertzel filters whose operating frequencies are distributed across the voice baseband are used to detect voice and control tones in a signal. Filters operating at frequencies of control tones and detecting that most of the signal energy occurs at those frequencies indicates presence of the control tones. At least three of the filters detecting that about 10% to 20% of the signal energy occurs at each of their operating frequencies indicate presence of voice. The total energy detected in the signal being below a noise threshold indicates presence of noise or silence.

 
Web www.patentalert.com

< Routing data based on comparative income values

< Electronic television program guide delivery system using telephone network idle time

> Network support for fax retry blocking

> Circuit arrangement for forming the termination of an analogous subscriber line

~ 00210