Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now


Blesser Talks PPM With House Oversight Committee Staff

His recent white paper catches attention on the Hill

Dr. Barry Blesser, director of engineering for 25-Seven Systems, is talking to the staff of the House Oversight and Government Reform Committee about the technical properties of the Arbitron Portable People Meter system.

He tells Radio World that the committee asked him to be a consultant to help its members understand the PPM system.

Years ago, the former MIT professor was an informal consultant to the Justice Department regarding the White House taping system during the Watergate scandal. (Blesser also writes a regular column for Radio World’s Engineering Extra.)

Since June, the committee, chaired by Rep. Edolphus Towns, D-N.Y., has been looking into whether the PPM under represents minorities. Arbitron has been cooperating with the committee and has been increasing its sample targets for minorities in PPM.

Blesser tells Radio World the committee saw his recent white paper on PPM and wanted to gain more understanding of the system. In the paper, published in August, Blesser studied publicly available PPM patents and talked to knowledgeable station engineers and consultants about the electronic ratings measurement system. He raises questions that he said he has not seen addressed elsewhere about PPM encoding performance, especially for different formats. In the document, Blesser offers information to stations on how they might test the robustness of their PPM encoding.

According to Blesser, the PPM system encodes digital station identification data in the 1 to 3 kHz region only when there is adequate audio energy in that spectral region. With inadequate energy in this region, a station’s audio might be “marginally encoded” or fragile, rather than robust, he says. Fragile encoding may then result in portable meters failing to detect the station. In his paper, he frames relevant questions he believes the industry should be asking about the PPM system and provides suggestions for station experiments.

Arbitron has recently issued PPM encoding policy briefs to stations outlining how a station should interpret the status indicators on PPM monitors and encoders. Another brief includes information on how all formats may be encoded, including formats with quieter music passages or brief pauses. The company plans to hold a PPM encoding Webinar next Friday, Nov. 20, for customers. Arbitron declined comment for this story.

Blesser said he wrote his paper because some customers and colleagues noticed variances between the PPM and diary ratings and they wanted technical assistance in evaluating the possibility that technical defects and limitations contributed to that variance. Some users of 25-Seven’s Audio Time Manager and Program Delay Manager wanted assurance that these products did not interfere with the PPM encoding process; Blesser says they don’t.

Blesser stressed to the committee that the PPM technology can only be understood as a complex system, rather than as a combination of isolated components.

His paper is available on the home page of the 25-Seven Web site.