| 摘要 |
<p>A pulse train processor (24) includes a plurality of parallel input, serially coupled pulse discriminating modules (26, 28, 30) one for each of the consecutive pulses of a pulse train characteristic of a magnetic strip or resonant tag target (18) signal produced in a magnetic interrogation zone such as found in retail clothing or library theft prevention applications. Each module is tailored to the particular expected characteristics of the corresponding pulse of the pulse train, and the modules are serially enabled and an alarm (36) is triggered if and only if the expected characteristics of the several pulses are sequentially present from the initial pulse to the last pulse of the received pulse train. The modules are self-resetting in the event that the pulse characteristics of any of the pulses are other than the expected pulse characteristics whereby the pulse train processor is substantially continuously armed. The modules are responsive to pulse sequence, pulse polarity, pulse height, and minimum and maximum duration of the several constitutive pulses of the pulse train whereby an ultra-high detection reliability is provided.</p> |
