US5390168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radio frequency transmission circuit
Assignee: Nokia Oyj
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Filing: 1992-09-21
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Granted: 1995-02-14
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Expires: 2012-09-21
Abstract
Abstract A radio frequency transmission circuit comprising a first signal generating means and a second signal generating means, means for modulating one of the first and second signals to produce a modulated signal, and mixer means to combine the other of the first and second signals and the modulated signal to produce an RF output signal. The first signal is controlled by a feed back loop comprising a second mixer having an input from both the first and second signals, whereby fluctuations in the frequency of the second signal are compensated for by adjustment of the first signal so as to maintain the RF output signal at a substantially constant frequency.
Inventors
- 👤 Markku Vimpari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:05
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/02; H03C3/09; H03C3/0908; H03C3/0983; H03C3/0916; H03C3/0933; H03L; H03L7/00; H03L7/06; H03L7/16; H03L7/18; H03L7/183; H03L7/185; H03C2200/00; H03C2200/0037; H03C2200/0058; H04; H04B; H04B1/00; H04B1/02; H04B1/04; H04B2001/0491
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
168 words
A radio frequency (RF) transmission circuit comprising: means for generating a first signal having a first frequency, means for generating a second signal having a second frequency, means for modulating one of said first and second signals with a further signal to produce a modulated signal, first mixer means for combining the other of said first and second signals with the modulated signal to produce an RF output signal, and a feedback circuit associated with the first signal generating means for controlling the frequency of the first signal, characterized by second mixer means associated with the first signal generating means for combining the first signal and the second signal to produce a combined signal, and the second mixer means being included in the feedback circuit associated with the first signal generating means, whereby the first signal is adjusted to compensate for variations in the second signal by maintaining the frequency of the combined signal substantially constant and thereby maintaining the frequency of the RF output signal substantially constant.
Claim 2
Dependent Claim
168 words
A radio frequency (RF) transmission circuit comprising: means for generating a first signal having a first frequency, means for generating a second signal having a second frequency, means for modulating one of said first and second signals with a further signal to produce a modulated signal, first mixer means for combining the other of said first and second signals with the modulated signal to produce an RF output signal, and a feedback circuit associated with the first signal generating means for controlling the frequency of the first signal, characterized by second mixer means associated with the first signal generating means for combining the first signal and the second signal to produce a combined signal, and the second mixer means being included in the feedback circuit associated with the first signal generating means, whereby the first signal is adjusted to compensate for variations in the second signal by maintaining the frequency of the combined signal substantially constant and thereby maintaining the frequency of the RF output signal substantially constant.
Claim 3
Dependent Claim
21 words
A radio frequency transmission circuit as claimed in claim 1, wherein the first signal has a frequency in the UHF range.
Claim 4
Dependent Claim
19 words
A radio frequency transmission circuit as claimed in claim 1, wherein the second signal is an intermediate frequency signal.
Claim 5
Dependent Claim
17 words
A radio frequency transmission circuit as claimed in claim 1, wherein the modulation means utilizes digital modulation.
Claim 6
Dependent Claim
20 words
A radio frequency transmission circuit as claimed in claim 4, wherein the digital modulation utilized involves Quadrature Phase Shift Keying.
Claim 7
Dependent Claim
17 words
A radio frequency transmission circuit as claimed in claim 1, wherein the modulation means utilizes analogue modulation.
Claim 8
Dependent Claim
29 words
A radio frequency transmission circuit as claimed in claim 1, wherein the feedback circuit comprises a Phase Locked Loop to which a substantially constant reference frequency may be applied.
Claim 9
Dependent Claim
21 words
A radio frequency transmission circuit as claimed in claim 7, wherein the reference frequency is generated by a Voltage Controlled Oscillator.
Claim 10
Dependent Claim
28 words
A radio frequency transmission circuit as claimed in claim 1, wherein the feedback circuit comprises a filter coupled to receive the combined signal from the second mixer means.
Claim 11
Dependent Claim
17 words
A radio frequency transmission circuit as claimed in claim 9, wherein the filter is a bandpass filter.
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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) | 1998-02-13 | 1998-08-15 | 1999-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-13 | 2002-08-15 | 2003-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-13 | 2006-08-15 | 2007-02-14 | $7700.00 | Window Closed / Lapsed |