Small frequency step up or down converters using large frequency step synthesizers
January 21, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesDouble super-heterodyne receiver Circuit arrangement for a wide-band VHF-UHF television double superheterodyne receiver Switchable filter circuits Method and apparatus for eliminating interference due to spurious signals generated in synthesized receivers Double conversion tuner with split IF output Synchronous up-conversion direct digital synthesizer Low phase noise agile up converter Frequency translating circuit with multiple stages using common local oscillator Patent #: 5220688 InventorAssigneeApplicationNo. 184572 filed on 01/21/1994US Classes:455/260, Phase lock loop or frequency synthesizer348/735, Automatic frequency control455/76, Synthesizer455/209, Plural local oscillators or mixers455/316With frequency stabilization for at least one local oscillatorExaminersPrimary: Urban, Edward F.Assistant: Wisler, Mark D. Attorney, Agent or FirmInternational ClassesH04B 001/26H04N 005/50 AbstractA double conversion frequency converter includes first and second mixing stages. The first mixing stage includes a first programable Local Oscillator (LO) synthesizer and a first mixer, and the second mixing stage includes a second programable LO synthesizer and a second mixer. The first and second LO synthesizers have a wide band tuning range for receiving a separate predetermined reference signal and generating therefrom first and second LO output signals, respectively, which each are changeable by predetermined large frequency steps. The first mixer mixes an input signal to the frequency converter with the first LO output signal for generating a first predetermined mixer output signal. The second mixer mixes a predetermined sideband generated in the first predetermined mixer output signal with the second LO output signal for generating a second predetermined mixer output signal which is use for the output signal for the frequency converter. The predetermined output signal of the frequency converter is changed in small frequency steps (e.g., at least 1 KHz) by concurrently changing each of the first and second LO output signals using large frequency step changes (e.g., at least 125 KHz) whereby the difference between the large frequency steps in the first and second LO output signals is equal to the small frequency step of the predetermined output signal.Field of SearchWith plural conversionWith synchronized or controlled local oscillator Plural local oscillators or mixers Synthesizer With tuning Plural separate successive conversions With plural separate local oscillators With frequency stabilization for at least one local oscillator Unwanted oscillation or radiation prevention With specified local oscillator structure or coupling Automatic Utilizing particular local oscillator control Reference oscillator or source Phase lock loop or frequency synthesizer With local oscillator synchronization or locking Demodulator Tuning Search tuning Automatic frequency control | |
