US4281408A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital signal processing arrangement for controlling the level of a frequency-division multiplex signal
Assignee: Nokia of America Corp
•
Filing: 1979-05-21
•
Granted: 1981-07-28
•
Expires: 1999-05-21
Abstract
Abstract Level control arrangement for frequency-division multiplex signals, comprising an amplifying device having a variable gain factor, a circuit for transposing the frequency of the multiplex signal at the output of said arrangement in order to bring the frequency of the pilot signal to a low frequency; a low-pass filter for limiting the spectrum of the transposed signal; and analog-to-digital converter in the form of a uniform delta modulator, the input whereof is connected to the output of the low-pass filter. In a code converter this delta modulation signal is converted into either a PCM signal, or a DPCM signal, and the signal thus obtained is applied to a digital filter for selecting a signal which is characteristic of said pilot signal. The filtered signal is applied to a detector for detecting the peak values. The peak values obtained are applied to a comparison device for generating an error signal which sets the value of the gain factor of the amplifying device.
Inventors
- 👤 Georges Bonnerot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:51
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/10
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
246 words
A level control arrangement for controlling the level of a frequency-division multiplex signal which includes a pilot signal, the level control arrangement comprising an amplifier having an adjustable gain factor and having means responsive to a setting signal for adjusting the gain factor thereof, setting signal-generating means coupled to the output of said amplifier and comprising: =frequency transposition means for transposing the frequency range of the multiplex signal to lower the frequency of the pilot signal; =a low-pass filter which has its input coupled to the output of the frequency transposition means; =converting means for converting an analog signal into a digital signal, the input of the converting means being connected to the output of said low-pass filter; =digital filter means, having an input connected to the output of the converting means, for generating a digital output signal which is characteristic of said pilot signal; and =means for comparing the peak value of the output of the digital filter means with a reference level to produce the setting signal for application to the amplifier; which level control arrangement is characterized in that said converting means comprise: a delta modulator for generating a delta-modulation signal, the delta modulator being controlled by sampling pulses occuring with a sampling rate Fe and which has its input connected to the output of the low-pass filter; and means for converting the delta-modulation signal into a permuted signal whose code words occur with a frequency Fe/2 n , n representing an integer.
Claim 2
Dependent Claim
246 words
A level control arrangement for controlling the level of a frequency-division multiplex signal which includes a pilot signal, the level control arrangement comprising an amplifier having an adjustable gain factor and having means responsive to a setting signal for adjusting the gain factor thereof, setting signal-generating means coupled to the output of said amplifier and comprising: =frequency transposition means for transposing the frequency range of the multiplex signal to lower the frequency of the pilot signal; =a low-pass filter which has its input coupled to the output of the frequency transposition means; =converting means for converting an analog signal into a digital signal, the input of the converting means being connected to the output of said low-pass filter; =digital filter means, having an input connected to the output of the converting means, for generating a digital output signal which is characteristic of said pilot signal; and =means for comparing the peak value of the output of the digital filter means with a reference level to produce the setting signal for application to the amplifier; which level control arrangement is characterized in that said converting means comprise: a delta modulator for generating a delta-modulation signal, the delta modulator being controlled by sampling pulses occuring with a sampling rate Fe and which has its input connected to the output of the low-pass filter; and means for converting the delta-modulation signal into a permuted signal whose code words occur with a frequency Fe/2 n , n representing an integer.
Claim 3
Dependent Claim
50 words
A level control arrangement as claimed in claim 1, characterized in that the delta modulator is formed by a uniform delta modulator and the means for converting the delta modulation signal into the permuted signal is formed by an accumulator whose content is read at a rate Fe/2 n .
References Cited (Backward Citations)
US4009350A
Cited
US4103110A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-27 | 1985-01-26 | 1985-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-27 | 1989-01-26 | 1989-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-27 | 1993-01-26 | 1993-07-28 | $7700.00 | Window Closed / Lapsed |