Patent US4405840A successfully refreshed from Google Patents.
US3753115A
Expired / Lapsed
US
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Arrangement for frequency transposition of analog signals
Assignee: US Philips Corp
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Filing: 1972-01-04
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Granted: 1973-08-14
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Expires: 1992-01-04
Abstract
Abstract In an arrangement for transposition of the frequency band of an analog signal the analog signal is first converted into a digital signal in an analog-to-digital converter. The digital output of the converter is connected to a multistage shift register operated with shift pulses having a pulse width less than half the pulse width of the highest frequency analog signal. A first weighting network is connected to each stage of the shift register and multiplies the information in the associated stage by a factor corresponding to a Fourier expansion of a desired transfer function resulting in a digital bandpass filter. The output of the weighting network is combined in a combination network and reconverted into analog form in a digital-to-analog converter. In order to correct for distortions due to the limited number of shift register stages at least one additional weighting network is connected to the shift register stages for providing a transfer function with the same bandwidth as the transfer function provided by the first weighting network, although the transfer function of the additional weighting network is shifted in phase with respect to that of the first weighting network. As with the first weighting network a digital-to-analog converter connected to a combining network for the additional weighting network provides analog signals. The analog signals associated with the first weighting network modulate the output signal of a carrier frequency generator, while the analog signals associated with the additional weighting network modulate a phase shifted version of the output of the carrier frequency generator. The phase shifted modulated carrier is then subtracted from the modulated carrier in an additional combining network thereby removing the objectionable portions of the modulated carrier produced by the distortions from the shift register and first first weighting network.
Inventors
- 👤 Gerwen P Van
- 👤 R Sluyter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:08
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/0219; H03D; H03D7/00; H03H17/0223; H03H17/0233; H03H17/0236; H04; H04J; H04J1/00; H04J1/02; H04J1/04; H03D2200/00; H03D2200/0041; H03D2200/005; H03D2200/0052; H03D2200/0066; H03D2200/007; H03D2200/0088
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
433 words
An arrangement for frequency transposition of analog input signals in a given frequency band, comprising analog-to-digital converter means for providing a digital signal corresponding to the analog input signals, shift register means comprising a plurality of serially connected shift register elements for transferring the contents of a preceding shift register element to a succeeding shift register element in response to shift pulses, means connecting the output of the analog-to-digital converter to a first of the shift register elements, shift Pulse source means for providing shift pulses having a period shorter than one-half the period of the highest frequency in the given frequency band of the analog signals to the shaft register means, first weighting network means connected to each of the shift register elements for multiplying the contents of each shift register element by a factor corresponding to terms of the Fourier expansion of a desired bandpass filter transfer characteristic, a first combining network connected to the first weighting network means for summing the weighted output of the shift register elements every shift period of the shift register pulses, a second weighting network means connected to each of the shift register elements for multiplying the contents of each shift register element by a factor corresponding to terms of the Fourier expansion of the desired transfer characteristic shifted over a fixed phase angle, a second combining network connected to the second weighting network means for summing the output of the shift register elements weighted by the second weighting network means every shift period of the shift pulses, a first digital-toanalog converter connected to the first combining means for providing a first analog output signal filtered by the transfer characteristic of the first weighting network and the first combining means, a second digital-to-analog converter connected to the second combining means for providing a second analog output signal filtered by the transfer characteristic of the second weighting network and the second combining means, a carrier frequency generator, a first modulator means connected to the carrier frequency generator and to the first digital-toanalog converter for modulating the output of the carrier frequency generator with the first analog output signal, a phase shifter, a second modulator means connected to the carrier frequency generator through the phase shifter and connected to the second digital-to-analog converter for modulating the phase shifted output of the carrier frequency generator with the second analog output signal, and a combination network connected to the output of the first modulator means and the second modulator means for combining the modulated carrier from the first modulator with the phase shifted modulated carrier from the second modulator.
Claim 2
Dependent Claim
433 words
An arrangement for frequency transposition of analog input signals in a given frequency band, comprising analog-to-digital converter means for providing a digital signal corresponding to the analog input signals, shift register means comprising a plurality of serially connected shift register elements for transferring the contents of a preceding shift register element to a succeeding shift register element in response to shift pulses, means connecting the output of the analog-to-digital converter to a first of the shift register elements, shift Pulse source means for providing shift pulses having a period shorter than one-half the period of the highest frequency in the given frequency band of the analog signals to the shaft register means, first weighting network means connected to each of the shift register elements for multiplying the contents of each shift register element by a factor corresponding to terms of the Fourier expansion of a desired bandpass filter transfer characteristic, a first combining network connected to the first weighting network means for summing the weighted output of the shift register elements every shift period of the shift register pulses, a second weighting network means connected to each of the shift register elements for multiplying the contents of each shift register element by a factor corresponding to terms of the Fourier expansion of the desired transfer characteristic shifted over a fixed phase angle, a second combining network connected to the second weighting network means for summing the output of the shift register elements weighted by the second weighting network means every shift period of the shift pulses, a first digital-toanalog converter connected to the first combining means for providing a first analog output signal filtered by the transfer characteristic of the first weighting network and the first combining means, a second digital-to-analog converter connected to the second combining means for providing a second analog output signal filtered by the transfer characteristic of the second weighting network and the second combining means, a carrier frequency generator, a first modulator means connected to the carrier frequency generator and to the first digital-toanalog converter for modulating the output of the carrier frequency generator with the first analog output signal, a phase shifter, a second modulator means connected to the carrier frequency generator through the phase shifter and connected to the second digital-to-analog converter for modulating the phase shifted output of the carrier frequency generator with the second analog output signal, and a combination network connected to the output of the first modulator means and the second modulator means for combining the modulated carrier from the first modulator with the phase shifted modulated carrier from the second modulator.
Claim 3
Dependent Claim
46 words
An arrangement as claimed in claim 1, wherein the plurality of shift register elements is reduced to values at which the minimum attenuation in the stop-band range of the transfer characteristic of the bandpass filter is located in the range between 15 dB and 30 dB.
Claim 4
Dependent Claim
94 words
An arrangement as claimed in claim 1, wherein the second weighting network, the second combining network, the phase shifter and the second modulator comprise a correction circuit, wherein the arrangement comprises m-1 additional correction circuits, the phase difference between the phase angles of each additional correction circuit being equal to q pi /(m+1), where q not = (m+1) and q is an integer and where the phase difference is between 0 and 2 pi , the phase difference between carrier frequency phase shifters of each additional correction circuit being equal to q pi /(m+1).
Claim 5
Dependent Claim
94 words
An arrangement as claimed in claim 2, wherein the second weighting network, the second combining network, the phase shifter and the second modulator comprise a correction circuit, wherein the arrangement comprises m-1 additional correction circuits, the phase difference between the phase angles of each additional correction circuit being equal to q pi /(m+1), where q not = (m+1) and q is an integer and where the phase difference is between 0 and 2 pi , the phase difference between carrier frequency phase shifters of each additional correction circuit being equal to q pi /(m+1).
Claim 6
Dependent Claim
44 words
An arrangement as claimed in claim 1, adapted for frequency transposition of a Plurality of analog signals located in different partial bands of a frequency division multiplex, wherein the analog-to-digital converter and the shift register means connected thereto is common to all partial bands.
Claim 7
Dependent Claim
122 words
An arrangement as claimed in claim 1, wherein the analog-to-digital converter comprises a delta modulator, the delta modulator comprising a pulse code modulator, a level control signal generator means connected to the analog input signals for producing level control signals corresponding to amplitude ranges of the analog input signals, an amplitude modulator connected to the pulse code modulator and to the level control signal generator means for modulating the output of the pulse code modulator with the level control signals, an integrating network connected to the output of the amplifier modulator, and a difference producing network for subtracting the output of the integrating network from the analog input signals and for providing the result of the subtraction to the pulse code modulator.
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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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |