11.   A PCS is similar to a cellular-phone system, though it operates at a higher frequency and can accommodate more subscribers in a particular band width.

12.   A PCS is similar to a cellular phone system, though it operates at a higher frequency.

13.   But some digital signals transmit at higher frequencies than analog signals and are more susceptible to energy loss as they travel between points.

14.   CT scans use higher frequency radiation but with a light receptor on the other side of the patient, creating highly accurate slices of the body on film.

15.   Digital phones, in particular, are likely to fade as the distance from a cell site increases because they operate at higher frequencies.

16.   Dogs, for example, hear much higher frequencies.

17.   DSL signals travel at a higher frequency over the same wire and do not interfere with phone calls.

18.   Higher frequency reproduction is expected to give the audio DVD a much better sound quality than a CD.

19.   Higher frequencies and rising capacity will require more filters in base stations and cell phones, says First Union analyst Roberts.

20.   Higher frequencies produce images with better resolution, which makes them useful for scanning organs closer to the surface, like the thyroid gland or testicles.