US Patent No. 9,088,272

FREQUENCY SHIFT-KEYING READER CIRCUIT


Patent No. 9,088,272
Issue Date July 21, 2015
Title Frequency Shift-keying Reader Circuit
Inventorship Tzyy-Sheng Horng, Kaohsiung (TW)
Rong-Fu Ye, Kaohsiung (TW)
Jian-Ming Wu, Kaohsiung (TW)
Assignee NATIONAL SUN YAT-SEN UNIVERSITY, Kaohsiung (TW)

Claim of US Patent No. 9,088,272

1. A frequency shift-keying reader circuit includes:
a band-pass filter for receiving a radio frequency signal and performing a filtering procedure, wherein the radio frequency
signal comprises an operational frequency;

a low noise amplifier for connecting to the band-pass filter and receiving the filtered radio frequency signal, wherein the
low noise amplifier is used for amplifying the radio frequency signal to provide an injection signal;

a first balun for connecting to the low noise amplifier and receiving the injection signal, the first balun generates the
first differential signal and the second differential signal, wherein the first differential signal and the second differential
signal are mutually inverted;

an injection-lock divide-by-2 frequency divider for connecting to the low noise amplifier and receiving the injection signal,
wherein the injection-lock divide-by-2 frequency divider is locked at a lock frequency by the injection signal, the lock frequency
is half the operational frequency, the injection-lock divide-by-2 frequency divider provides a first oscillation signal and
a second oscillation signal, wherein the first oscillation signal and the second oscillation signal are mutually inverted;

a sub-harmonic mixer for connecting to the first balun and the injection-lock divide-by-2 frequency divider, the sub-harmonic
mixer receives the first differential signal, the second differential signal, the first oscillation signal and the second
oscillation signal for performing a mixing procedure and generates an output signal; and

a low-pass filter, the low-pass filter connects to the sub-harmonic mixer and performs a filtering procedure to the output
signal.