Radio signal controlled digital clock

Claim 2

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals, said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency, said radio signals containing encoded time information including a multiplicity of binary coded digits representing the current time; processing means coupled to said receiver means for decoding the time information contained in said time-based radio signal, including: data collecting means for decoding and storing the binary bits encoded in said time-based radio signal; and digit verification means for determining the digit values represented by said decoded binary bits, including scoring means for each of a multiplicity of said digits for scoring each potential value of said digit in accordance with the number of said decoded bits which are consistent with said potential value, and verifying means for verifying one of said potential digit values as the correct value when the score for said one potential digit value exceeds the scores for all of the other potential digit values by at least a specified threshold value; and output means for generating a verified time signal corresponding to digit values verifyied by said verifying means.

Claim 3

A radio signal controlled clock as set forth in Claim 1, wherein said encoded time information in said time-based radio signals includes clock reference signals for demarking a predefined time period; said processing means including: oscillator means for generating a periodic signal; internal counter means for keeping track of the passage of time in accordance with said periodic signal generated by said oscillator means; means for synchronizing said internal counter means with said clock reference signals, and for determining the amount said internal counter is adjusted each time said internal counter is synchronized with said clock reference signals; and means for accumulating said adjustment amounts, and for determining the average adjustment made over a period of time; said means for synchronizing further including means for periodically adjusting said internal counter in accordance with said average adjustment when said clock reference signals are not received by said receiver and whenever said clock reference signals are otherwise not available to said means for synchronizing; whereby said internal counter means can be kept ap­proximately synchronized with said clock reference signals even when said clock reference signals are not available.

Claim 4

A radio signal controlled clock as set forth in Claim 1, Wherein said encoded time information in said time-based radio signals is arranged in accordance with a predefined format and includes marker information usable for determin­ing the relative locations of said binary bits in said predefined format; said data collecting means includes means for decoding and storing said binary bits while also decoding the marker information in said time-based radio signals and thereby determining the relative locations of said encoded bits in said predefined format; said digit verification means includes means for using said binary bits decoded and stored by said data collecting means while decoding said marker information to determine the relative locations of said bits in said predefined format; whereby said clock can collect data usable for digit verification even before decoding said marker information to determine the relative locations of said encoded bits in said predefined format.

Claim 5

A radio signal controlled clock as set forth in Claim 1, wherein said decoded digit values generated by said digit verification means comprise a verified time value, and said processing means includes lockon verifying means for select­ing an output timebase value, including first timebase means for storing a first timebase value and a first confidence value corresponding to the reliability of said first timebase value, said first timebase value comprising the selected output timebase value; second timebase means for storing a second timebase value and a second confidence value corresponding to the reliability of said second timebase value; timebase updating means for updating said first and second timebase values, including: timebase value updating means for storing the verified time value generated by said digit verification means in said first timebase means when said decoded time value is not inconsistent with said first timebase value, if any, and for storing said verified time value in said second timebase means when said decoded time value is inconsistent with said first timebase value and not inconsistent with said second timebase value, if any; confidence updating means for (a) increasing said first confidence value relative to said second con­fidence value when said decoded time value is not inconsis­tent with said first timebase value, and (b) increasing said second confidence value relative to said first confidence value when said decoded time value is inconsistent with said first timebase value and not inconsistent with said second timebase value; and output timebase replacing means for replacing the timebase stored in said first timebase means with the timebase stored in said second timebase means when said second confidence value exceeds said first confidence level; and said output means generates a time signal cor­responding to said selected output timebase.

Claim 6

A radio signal controlled clock as set forth in claim 4, said timebase value updating means including means for clearing said second timebase value and second confidence value stored by said second timebase means when said second confidence value exceeds said first confidence level; said timebase value updating means for storing said verified time value in said second timebase means when said verified time value is inconsistent with said first timebase value and said second timebase value has been cleared.

Claim 7

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals contain­ing encoded time information in accordance with a predefined format, said time information including clock reference signals for demarking a predefined time period; said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency; processing means coupled to said receiver means for decoding the time information contained in said time-based radio signals, including: oscillator means for generating a periodic signal; internal counter means for keeping track of the passage of time in accordance with said periodic signal generated by said oscillator means; means for synchronizing said internal counter means with said clock reference signals, and for determining the amount said internal counter is adjusted each time said internal counter is synchronized with said clock reference signals; means for accumulating said adjustment amounts, and for determining the average adjustment made over a period of time; said means for synchronizing further including means for periodically adjusting said internal counter in accordance with said average adjustment when said clock reference signals are not received by said receiver and whenever said clock reference signals are otherwise not available to said means for synchronizing; whereby said internal counter means can be kept ap­proximately synchronized with said clock reference signals even when said clock reference signals are not available.

Claim 8

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals contain­ing encoded time information in accordance with a predefined format, said time information including clock reference signals for demarking a predefined time period; said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency; processing means coupled to said receiver means for decoding the time information contained in said time-based radio signals, including: oscillator means for generating a periodic signal; internal counter means for keeping track of the passage of time in accordance with said periodic signal generated by said oscillator means; means for synchronizing said internal counter means with said clock reference signals, and for determining the amount said internal counter is adjusted each time said internal counter is synchronized with said clock reference signals; means for accumulating said adjustment amounts, and for determining the average adjustment made over a period of time; said means for synchronizing further including means for periodically adjusting said internal counter in accordance with said average adjustment when said clock reference signals are not received by said receiver and whenever said clock reference signals are otherwise not available to said means for synchronizing; whereby said internal counter means can be kept ap­proximately synchronized with said clock reference signals even when said clock reference signals are not available.

Claim 9

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals contain­ing encoded time information in accordance with a predefined format, said time information including a multiplicity of binary coded digits representing the current time and marker information usable for determining the relative locations of said binary bits in said predefined format; said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency; control means coupled to said receiver means for specifying the carrier frequency to be received by said receiver means, and for decoding the time information contained in said time-based radio signal, including: data collecting means for decoding and storing the binary bits encoded in said time-based radio signal, includ­ing means for decoding and storing said binary bits while also decoding the marker information in said time-based radio signals and thereby determining the relative locations of said encoded bits in said predefined format; and time information decoding means for generating a decoded time value by determining the values of said multi­plicity of binary coded digits representing the current time using said decoded binary bits stored by said data collect­ing means, including means for using said binary bits decoded and stored while decoding said marker information to determine the relative locations of said bits in said predefined format; and output means for generating a time signal cor­responding to said decoded time value; whereby said clock can collect data usable for time decoding even before decoding said marker information to determine the relative locations of said encoded bits in said predefined format.

Claim 10

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals contain­ing encoded time information in accordance with a predefined format, said time information including a multiplicity of binary coded digits representing the current time and marker information usable for determining the relative locations of said binary bits in said predefined format; said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency; control means coupled to said receiver means for specifying the carrier frequency to be received by said receiver means, and for decoding the time information contained in said time-based radio signal, including: data collecting means for decoding and storing the binary bits encoded in said time-based radio signal, includ­ing means for decoding and storing said binary bits while also decoding the marker information in said time-based radio signals and thereby determining the relative locations of said encoded bits in said predefined format; and time information decoding means for generating a decoded time value by determining the values of said multi­plicity of binary coded digits representing the current time using said decoded binary bits stored by said data collect­ing means, including means for using said binary bits decoded and stored while decoding said marker information to determine the relative locations of said bits in said predefined format; and output means for generating a time signal cor­responding to said decoded time value; whereby said clock can collect data usable for time decoding even before decoding said marker information to determine the relative locations of said encoded bits in said predefined format.

Claim 13

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals, said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency, said radio signals containing encoded time information including a multiplicity of binary coded digits representing the current time;; data collecting means for decoding and storing the binary bits encoded in said time-based radio signal; time information decoding means for generating a decoded time value by determining the values of said multiplicity of binary coded digits representing the current time using said decoded binary bits stored by said data collecting means, including digit verification means for verifying said decoded time value represented by said decoded binary bits and generating a verified time value; lockon verifying means for selecting an output timebase value, including first timebase means for storing a first timebase value and a first confidence value corresponding to the reliability of said first timebase value, said first timebase value comprising the selected output timebase value; second timebase means for storing a second timebase value and a second confidence value corresponding to the reliability of said second timebase value; timebase updating means for updating the values of said first and second timebase means, including: timebase value updating means for storing the verified time value generated by said digit verification means in said first timebase means when said decoded time value is not inconsistent with said first timebase value, if any, and for storing said verified time value in said second timebase means when said decoded time value is inconsistent with said first timebase value and not inconsistent with said second timebase value, if any; confidence updating means for (a) increasing said first confidence value relative to said second con­fidence value when said decoded time value is not inconsis­tent with said first timebase value, and (b) increasing said second confidence value relative to said first confidence value when said decoded time value is inconsistent with said first timebase value and not inconsistent with said second timebase value; and output timebase replacing means for replacing the timebase stored in said first timebase means with the timebase stored in said second timebase means when said second confidence value exceeds said first confidence level; and output means for generating a time signal cor­responding to said selected output timebase.

Claim 14

A radio signal controlled clock for keeping time in accordance with broadcast time-based radio signals, said clock comprising: receiver means for receiving broadcast time-based radio signals at a specified carrier frequency, said radio signals containing encoded time information including a multiplicity of binary coded digits representing the current time;; data collecting means for decoding and storing the binary bits encoded in said time-based radio signal; time information decoding means for generating a decoded time value by determining the values of said multiplicity of binary coded digits representing the current time using said decoded binary bits stored by said data collecting means, including digit verification means for verifying said decoded time value represented by said decoded binary bits and generating a verified time value; lockon verifying means for selecting an output timebase value, including first timebase means for storing a first timebase value and a first confidence value corresponding to the reliability of said first timebase value, said first timebase value comprising the selected output timebase value; second timebase means for storing a second timebase value and a second confidence value corresponding to the reliability of said second timebase value; timebase updating means for updating the values of said first and second timebase means, including: timebase value updating means for storing the verified time value generated by said digit verification means in said first timebase means when said decoded time value is not inconsistent with said first timebase value, if any, and for storing said verified time value in said second timebase means when said decoded time value is inconsistent with said first timebase value and not inconsistent with said second timebase value, if any; confidence updating means for (a) increasing said first confidence value relative to said second con­fidence value when said decoded time value is not inconsis­tent with said first timebase value, and (b) increasing said second confidence value relative to said first confidence value when said decoded time value is inconsistent with said first timebase value and not inconsistent with said second timebase value; and output timebase replacing means for replacing the timebase stored in said first timebase means with the timebase stored in said second timebase means when said second confidence value exceeds said first confidence level; and output means for generating a time signal cor­responding to said selected output timebase.

Claim 15

A radio signal controlled clock as set forth in claim 9, said confidence updating means including means for decreas­ing said first confidence value when said verified time value is inconsistent with said first timebase value and not inconsistent with said second timebase value.

Claim 16

A radio signal controlled clock as set forth in claim 9, said timebase value updating means including means for clearing said second timebase value and second confidence value stored by said second timebase means when said second confidence value exceeds said first confidence level; said timebase value updating means for storing said verified time value in said second timebase means when said verified time value is inconsistent with said first timebase value and said second timebase value has been cleared.