Patent ID: 8312551

Claim:
A method for tamper detection of a transmitted signal, comprising: generating a first digital data signal containing payload data and having a first data rate; generating a second digital data signal containing an integrity code and having a second data rate; concurrently transmitting said first digital data signal at a first carrier frequency using a first modulation format, and said second digital data signal at a second carrier frequency using a second modulation format; selecting said second carrier frequency and a bandwidth of said second digital data signal so that said second digital data signal is contained within a frequency spectrum defined by a bandwidth of said first digital data signal; tracking symbol timing of said first digital data signal; using said tracked symbol timing to lock to said second digital data signal which has a symbol timing that is rationally related to and derived from said tracked symbol timing of said first digital data signal; and verifying an integrity of said first digital data signal at a remote receiver based on detection at said remote receiver of said second digital data signal, wherein said verifying step comprises identifying said integrity code within said second digital data signal; and responsive to said verifying step, automatically performing at said remote receiver actions including (1) notifying a user that tampering has occurred with respect to a composite signal comprising said first digital data signal and said second digital data signal, and (2) discarding said payload data contained in said first digital data signal.