| 摘要 |
A vehicle steering wheel lock with a burglar-proof alarm device comprises a burglar-proof alarm circuit, A wireless signal detecting unit, an air pressure detecting unit; supersonic detecting unit for detecting movements of objects; an infrared receiver for receiving infrared signals from the portable alarm device. The wireless wave emitting unit includes a receiving antennal circuit, a high frequency amplifier, a band pass filter, a local oscillating circuit, a mixing circuit, a middle frequency circuit, and a second middle frequency IC; the receiving antenna circuit being for adjusting the harmonic receiving frequency for receiving high frequency signal, which is then passed through the high frequency amplifier, band pass filter, local oscillating circuit, and the mixing circuit; the local oscillator circuit having a baseband oscillating circuit, a nine-time amplifier circuit, a nine-time frequency modulating circuit for generating an oscillating frequency signal to the mixing circuit.
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