US 8,265,191 B2Granted

Receiver for object locating and tracking systems and related methods

AssigneeZebra Enterprise Solutions Corp.

InventorsDouglas C. Bowman, Huong M. Hang

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Abstract

A communications system, such as part of a real-time location system, includes a transmitter that can be part of a location processor, tag emission reader or tag interrogator that generates a frequency shift key (FSK) modulated wireless communication signal representative of digital data and transmits the communications signal over a wireless communications channel. A receiver such as incorporated within a tag transceiver used in the real-time location system receives the FSK modulated communication signal. The receiver includes a circuit for calculating the magnitude of low and high tones of the FSK modulated communication signal and a threshold for amplitude shift keyed (ASK) channel data and FSK channel data to derive the digital data even in the presence of on-tone jammers in the communications channel.

Claims25

Dependent claims

A communication system, comprising:

a transmitter configured to generate a wireless communications signal representative of digital data by modulating the digital data using Frequency Shift Keyed (FSK) modulation, and transmit the wireless communications signal over a wireless communications channel as an FSK modulated communications signal;
and
a receiver configured to receive the FSK modulated communications signal and generate receiver output data, the receiver comprising circuitry configured to:
convert the FSK modulated communications signal via an analog-to-digital conversion;
determine a low tone magnitude signal and a high tone magnitude signal from the converted FSK modulated communications signal;
generate an FSK data channel by comparing the low tone magnitude signal to the high tone magnitude signal;
determine a low tone threshold based on the low tone magnitude via low tone peak-hold circuitry;
generate a low tone Amplitude Shift Keyed (ASK) data channel by comparing the low tone magnitude signal with the low tone threshold;
determine a high tone threshold based on the high tone magnitude via high tone peak-hold circuitry;
generate a high tone Amplitude Shift Keyed (ASK) data channel by comparing the high tone magnitude signal with the high tone threshold;
determine that data on the FSK data channel is invalid data;
and
in response to determining that the data on the FSK data channel is invalid data, process the low tone ASK data channel to generate the receiver output data or process the high tone ASK data channel to generate the receiver output data.

10 more elements

A receiver for processing a wireless communications signal representative of digital data that has been Frequency Shift Key (FSK) modulated to generate receiver output data, the receiver comprising:

an analog-to-digital converter configured to receive the FSK modulated communications signal over a communications channel and convert the FSK modulated communications signal into a digital signal;
and
circuitry configured to:
determine a low tone magnitude signal and a high tone magnitude signal from the converted FSK modulated communications signal;
generate an FSK data channel by comparing the low tone magnitude signal to the high tone magnitude signal:
determine a low tone threshold based on the low tone magnitude via low tone peak-hold circuitry;
generate a low tone Amplitude Shift Keyed (ASK) data channel by comparing the low tone magnitude signal with the low tone threshold:
determine a high tone threshold based on the high tone magnitude via high tone peak-hold circuitry;
generate a high tone Amplitude Shift Keyed (ASK) data channel by comparing the high tone magnitude signal with the high tone threshold:
determine that data on the FSK data channel is invalid data;
and
in response to determining that the data on the FSK data channel is invalid data, process the low tone ASK data channel to generate the receiver output data or process the high tone ASK data channel to generate the receiver output data.

9 more elements

Dependencies are inferred from the claim text.