John P. Wargo, associate professor of environmental policy and risk analysis at the School of Forestry and Environmental Studies, recently was interviewed by United Press International radio news service. The topic was his book, "Our Children's Toxic Legacy: How Science and Law Fail to Protect Us from Pesticides," published in September by Yale University Press.
Most listeners probably thought Professor Wargo, who was on campus, was sitting in the same room with the radio interviewer, who was in California. The conversation's clarity of sound, however, was due to new digital technology now available at the University.
A specially equipped High Quality Audio Conferencing studio, located in the Audio Visual Center at 59 High St., uses the same basic technology that makes it possible to capture and transmit high-quality sound on compact discs, according to John Meickle, director of planning and technology for ITS Telecommunications at Yale.
Sound is digitized in the audio conferencing studio by equipment called a "codec," an abbreviation for "code and decode." The sound is then transmitted on a digital telephone line -- known as an Integrated Services Digital Network - ISDN- line -- and reconstructed on the other end by a similar codec. The telephone line connecting the two codecs runs at 128 kilobits per second and is immune to the loss and noise commonly found on analog telephone lines, Mr. Meickle says.
"Standard telephone lines are only capable of passing up to 3 kilohertz, the range of a conversational voice. The human ear, which can hear well beyond 3 kilohertz, permits us to notice the missing information and recognize that the sound is limited or distorted," he explains. "The analog telephone line connecting the remote speaker to the radio station also contributes to loss of signal strength and picks up electromagnetic noise from other lines, further decreasing fidelity."
Generally, this standard connection is not suitable for singing, for instrumental music or for interviews where the full richness of the human voice is important. Putting the audio codec together with the ISDN line yields an audio range of 40 hertz to more than 18,000 hertz, almost the full range found on an audio CD, Mr. Meickle notes. It permits the nuances of a voice, the resonance of instruments, or the true silence between words or notes to be heard without the static or muffling previously associated with remote broadcasts
To schedule studio time for an ISDN radio interview, call the Office of Public Affairs at 432-1333 or John Schilke at the Audio Visual Center, 432-2659.