Means for Automatically Setting Broadcast Radio Receivers to Local Time
Original Publication Date: 2004-Jun-08
Included in the Prior Art Database: 2004-Jun-08
National Institute of Standards and Technology
This disclosure describes a simple addition to the first-generation in-band on-channel (IBOC) broadcast radio standard tht enbales and simplifies the use of new types of radio-controlled clocks, watches, and other time-keeping devices - including the aural radio receivers themselves. The invention consists of localization data that are added to the broadcast signal to enable receivers to determine their local time zone, the local practice in observing Daylight Saving Time (DST), and whether or not DST is in effect regiionally (nationally), regardless of local practice.
Time Dissemination Using In-Band On-Channel Broadcast Radio
Inventor: Jonathan Hardis (840)
This disclosure describes a simple addition to the first-generation in-band on-channel (IBOC) broadcast radio standard that enables and simplifies the use of new types of radio-controlled clocks, watches, and other time-keeping devices—including the aural radio receivers themselves. The invention consists of localization data that are added to the broadcast signal to enable receivers to determine their local time zone, the local practice in observing Daylight Saving Time (DST), and whether or not DST is in effect regionally (nationally), regardless of local practice.
Purpose of Invention
The invention reduces or eliminates the need for users to set the local time in broadcast radio receivers and other consumer electronics. The problem addressed is the one that leads to videocassette recorders (VCRs) constantly flashing a time of 12:00—that is, the difficulty users have in programming modern electronic devices. The invention addresses this problem for the next generation of broadcast radio receivers, and by extension any other devices that may wish to utilize broadcast radio solely to set a clock (e.g., wall clocks, microwave ovens, set-back thermostats, etc.).
Introduction and Background
Dissemination of the correct time through radio broadcasting is a well-established concept.
The National Bureau of Standards (NBS), the predecessor agency to the National Institute of Standards and Technology (NIST), began broadcasting timing signals from short-wave radio station WWV in 1923. Today this radio station is located in Fort Collins, Colorado. Its sister station WWVH in Kauai, Hawaii, began service in 1948. Since 1956, a separate long-wave service, WWVB, has also broadcast from Colorado. NIST Special Publication 432 describes in detail these broadcast services and the digital signals they provide .
As important as these radio services are for maintaining standard time throughout the United States, neither their broadcast power nor propagation characteristics make them entirely suitable for broad consumer application. This is in contrast to Europe where, owing to the shorter distances involved, German radio station DCF 77 (similar in characteristic to WWVB) has enabled the widespread use of radio-synchronized clocks and watches . Similarly, the satellite line-of-sight requirement for obtaining time signals from the Global Positioning System (GPS) satellites makes this an awkward system for consumer clocks.
In the United States, efforts at using mass media for time dissemination have hitherto focused on broadcast television. In the early 1970’s, NBS developed a time distribution system that placed a hidden time code on an unused part of the broadcast television signal. A decoder in the television set could recover and display the time. However, there was little need in the 1970’s for using television sets as clocks, and the system was no...