US5301367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct digital synthesizer for producing a modulated intermediate frequency in a radio apparatus
Assignee: Nokia Oyj
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Filing: 1992-08-25
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Granted: 1994-04-05
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Expires: 2012-08-25
Abstract
Abstract A synthesizer for a radio transceiver uses a Direct Digital Synthesis (DDS) system (3) to provide a modulated signal for the transmitter section. The modulated signal (So) is then mixed in a mixer (4) using a signal from a local oscillator (1) to provide the signal for transmission. The reference frequency for the DDS system is provided by the local oscillator (1) of the receiver section. The local oscillator is used to provide the signal for the mixer (4).
Inventors
- 👤 Jarmo J. Heinonen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:53
CPC Classifications
H; H03; H03C; H03C3/00; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/403; H04B1/405
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
125 words
A synthesizer for a radio transceiver comprising: a local oscillator means for providing a local oscillator signal; a receiver section having a first mixer means coupled to said local oscillator means, for mixing a received radio frequency signal and said local oscillator signal and for generating an intermediate frequency signal; and a transmitter section comprising a direct digital synthesis means coupled to said local oscillator means for generating a modulated intermediate frequency signal, said local oscillator signal being employed by said direct digital synthesis means as a reference frequency signal, said transmitter section further comprising a second mixer means coupled to said local oscillator means for mixing said modulated intermediate frequency signal and said local oscillator signal and for generating a radio frequency transmission signal.
Claim 2
Dependent Claim
125 words
A synthesizer for a radio transceiver comprising: a local oscillator means for providing a local oscillator signal; a receiver section having a first mixer means coupled to said local oscillator means, for mixing a received radio frequency signal and said local oscillator signal and for generating an intermediate frequency signal; and a transmitter section comprising a direct digital synthesis means coupled to said local oscillator means for generating a modulated intermediate frequency signal, said local oscillator signal being employed by said direct digital synthesis means as a reference frequency signal, said transmitter section further comprising a second mixer means coupled to said local oscillator means for mixing said modulated intermediate frequency signal and said local oscillator signal and for generating a radio frequency transmission signal.
Claim 3
Dependent Claim
43 words
A synthesizer as recited in claim 1 wherein said direct digital synthesis means comprises a digital interface and a digital to analog converter, and is responsive to a frequency control digital value and a modulation input to produce said modulated intermediate frequency signal.
Claim 4
Dependent Claim
37 words
A synthesizer as recited in claim 1 wherein said transmitter section includes a multiplier circuit positioned between said direct digital synthesis means and said second mixer means for increasing a frequency of said modulated intermediate frequency signal.
Claim 5
Dependent Claim
23 words
A synthesizer according to claim 1 wherein said local oscillator means comprises a phase locked loop synthesizer that produces said local oscillator signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-04-04 | 1997-10-04 | 1998-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-04 | 2001-10-04 | 2002-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-04 | 2005-10-04 | 2006-04-05 | $7700.00 | Window Closed / Lapsed |