US3796952A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency-selective calibrated amplitude-measuring system
Assignee: Wandel and Golterman GmbH and Co
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Filing: 1972-04-24
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Granted: 1974-03-12
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Expires: 1992-04-24
Abstract
Abstract An incoming signal voltage of frequency fe, whose amplitude is to be measured, is additively heterodyned in a first mixer with a locally generated variable test frequency ft to provide a first beat frequency fi1 fe + ft clearing a first filter with a pass band including that beat frequency. In a second mixer, preceding a second filter with a narrow pass band centered on a second beat frequency fi2, the first beat frequency fi1 is subtractively heterodyned with a locally generated ancillary frequency fc of magnitude fi1 - fi2 to provide the frequency fi2 which passes the second filter and reaches an amplitude indicator through an adjustable amplifier or attenuator. In a calibrating position, a fixed reference frequency fo fi2 from a local oscillator is substituted for the input frequency fe whereas the test frequency ft is replaced by the ancillary frequency fc in the first mixer.
Inventors
- 👤 H Bayer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:29
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/0007; H; H04; H04B; H04B3/00; H04B3/02; H04B3/46; H04B3/48
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
283 words
A circuit arrangement for giving a calibrated amplitude reading of an alternating signal voltage of selected frequency, comprising: a first oscillator generating a fixed reference frequency fo; a second oscillator generating a widely variable test frequency ft1 a source of at most limitedly variable ancillary frequency fc; additive mixer means and subtractive mixer means connected in cascade; switch means having a measuring position for applying to a first one of said mixer means said test frequency ft and an input frequency fe of an incoming signal voltage, thereby generating a first beat frequency fi1 fe + OR - ft upon saiD test frequency ft bearing a predetermined relationship with said input frequency fe, said switch means further having a calibrating position for applying to the first mixer means said reference frequency fo and said ancillary frequency fc to synthesize said first beat frequency fi1 therefrom; a first band-pass filter, with a pass band including said first beat frequency fi1, connected between said first mixer means and the second mixer means for delivering to the latter said first beat frequency fi1, said second mixer means being further connected to said source for receiving therefrom in each of said positions said ancillary frequency fc to generate a second beat frequency fi2 fo; a second band-pass filter, with a narrow pass band centered on said second beat frequency fi2, connected in the output of said second mixer means for receiving therefrom said second beat frequency f12; amplitude-indicating means connected to said second mixer means for receiving said second beat frequency fi2 therefrom; and amplitude-adjusting means between said second mixer means and said amplitude-indicating means for setting same, in said calibrating position, to a selected reference value.
Claim 2
Dependent Claim
283 words
A circuit arrangement for giving a calibrated amplitude reading of an alternating signal voltage of selected frequency, comprising: a first oscillator generating a fixed reference frequency fo; a second oscillator generating a widely variable test frequency ft1 a source of at most limitedly variable ancillary frequency fc; additive mixer means and subtractive mixer means connected in cascade; switch means having a measuring position for applying to a first one of said mixer means said test frequency ft and an input frequency fe of an incoming signal voltage, thereby generating a first beat frequency fi1 fe + OR - ft upon saiD test frequency ft bearing a predetermined relationship with said input frequency fe, said switch means further having a calibrating position for applying to the first mixer means said reference frequency fo and said ancillary frequency fc to synthesize said first beat frequency fi1 therefrom; a first band-pass filter, with a pass band including said first beat frequency fi1, connected between said first mixer means and the second mixer means for delivering to the latter said first beat frequency fi1, said second mixer means being further connected to said source for receiving therefrom in each of said positions said ancillary frequency fc to generate a second beat frequency fi2 fo; a second band-pass filter, with a narrow pass band centered on said second beat frequency fi2, connected in the output of said second mixer means for receiving therefrom said second beat frequency f12; amplitude-indicating means connected to said second mixer means for receiving said second beat frequency fi2 therefrom; and amplitude-adjusting means between said second mixer means and said amplitude-indicating means for setting same, in said calibrating position, to a selected reference value.
Claim 3
Dependent Claim
18 words
A circuit arrangement as defined in claim 1 wherein said additive mixer means is said first mixer means.
Claim 4
Dependent Claim
27 words
A circuit arrangement as defined in claim 2 wherein the magnitude of said reference frequency fo is a small fraction of that of said ancillary frequency fc.
Claim 5
Dependent Claim
30 words
A circuit arrangement as defined in claim 1, further comprising adjustable step-down means for the amplitude of said signal voltage inserted between said switch means and said first mixer means.
Claim 6
Dependent Claim
16 words
A circuit arrangement as defined in claim 1 wherein said source is a fixed third oscillator.
Claim 7
Dependent Claim
19 words
A circuit arrangement as defined in claim 1 wherein said source comprises a variable oscillator provided with frequency-modulating means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |