Frequency Standards: CDMA Timing Technology

CDMA Timing
GPS-synchronized products require you to install a view-of-the-sky antenna.
CDMA-synchronized products work great with the antenna inside your building, just like your cell phone. (No subscriber fees required.)

CDMA cell phone towers transmit the timing signal. No subscriber fees to receive this signal.

Using CDMA cellular/PCS telephone signals as a precise time and frequency reference is the first innovation in timing technology since the introduction of GPS in the mid-1980's. We are the ONLY company to successfully incorporate this technology into high-quality precision timing products and have been shipping to enthusiastic customers since 2000.

Why Use CDMA?
The vast majority of precise timing products use GPS as their timing source. These products require an antenna installed with a large view-of-the-sky. Installing and maintaining the antenna can range from being merely a nuisance to being impossible. In many downtown locations running a cable to the roof can cost several thousands of dollars. In addition, leasing rooftop space can cost hundreds of dollars a month. We wanted to solve these problems and free you from the GPS antenna hassle.

How Is CDMA Used For Timing?
Our CDMA products harness the accuracy of GPS via CDMA signals used by digital cellular/PCS telephones. Each CDMA base station has at least one GPS receiver because its' transmissions must be precisely synchronized within ten microseconds. In effect, CDMA base stations act as GPS repeaters for time and frequency applications - an indirect form of GPS. That's why we sometimes call it "Indirect GPS".

Where Are CDMA Signals Available?
These very reliable signals are easily received inside buildings and are extensively available throughout North America, Brazil, China, Japan, Korea, India, Mongolia, New Zealand, Hong Kong and elsewhere. If you are located in one of these areas then chances are good that you have CDMA cellular/PCS coverage. If in doubt, give us a call.

More Details...
In the late 1980's Qualcomm designed a mobile, cellular telecommunications system offering numerous advantages over existing systems. This system has been widely accepted, standardized and deployed throughout the world. It is commonly referred to as CDMA due to its use of Code Division Multiple Access (CDMA) techniques for servicing multiple users on the same frequency. It is sometimes referred to as IS-95 after the TIA/EIA standard which defines its signal structure and protocols.

One of its most noteworthy characteristics is the specification of the GPS timescale as the CDMA mobile telecommunications system timescale. In so doing, Qualcomm in essence designed a system in which each of the base stations became a distributor of GPS time. Transmissions from CDMA base stations are precisely synchronized to UTC time to within ten microseconds. This has profound implications for users of precise time who are within receiving range of one of these base stations. Relative to the signals received by GPS receivers on the earth, signals from the CDMA mobile telecommunications systems are much stronger. This means that they are easily received inside buildings.