US3849744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Base-band delay equalizer
Assignee: NEC Corp
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Filing: 1973-04-24
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Granted: 1974-11-19
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Expires: 1993-04-24
Abstract
Abstract A base-band delay equalizer for compensating for envelope delay distortion in angle modulation transmission systems such as FDMFM multiplex telephone signal transmission, FM color television signal transmission or the like is disclosed. The base-band signal, which may be either the signal prior to angle modulation or subsequent to angle modulation, is applied to the delay equalizer which produces an envelope delay time which varies as a function of the base-band signal voltage. The base-band delay equalizer includes a variable-capacitance, such as a variablecapacitance diode, whose capacitance varies with the voltage of the input base-band signal.
Inventors
- 👤 T Furuya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:39
CPC Classifications
H; H04; H04B; H04B14/00; H04B14/002; H04B14/006; H04B1/00; H04B1/68
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
218 words
A base-band delay equalizer for equalizing delay time for all the frequency components of a base-band signal of broad frequency bandwidth to be transmitted over an angle modulation transmission system, said equalizer being disposed at the base-band signal circuit of at least one of the transmitting or receiving ends of said transmission system and comprises in combination: a variable-capacitance diode having a capacitance controllable in response to the voltage of said base-band signal applied thereto, input means for supplying to said variable-capacitance diode said base-band signal, output means for deriving from said variable-capacitance diode a delay-compensated base-band signal, said variable-capacitance diode being connected in shunt between said input and output means and ground, a first resistor connected in series between said input means and the junction of said variable-capacitance diode with said output means, a second resistor connected in common to said variablecapacitance diode and said output means and in shunt to ground such that the envelope time delay is approximated by Cd (R1R2/R1 + R2) where Cd is the junction capacity of said variable-capacitance diode and R1 and R2 are the resistances of said first and second resistors, respectively, and bias means for supplying to said variable-capacitance diode a direct-current bias voltage so as to set the non-input capacitance of said variable-capacitance diode at a suitable value.
Claim 2
Dependent Claim
218 words
A base-band delay equalizer for equalizing delay time for all the frequency components of a base-band signal of broad frequency bandwidth to be transmitted over an angle modulation transmission system, said equalizer being disposed at the base-band signal circuit of at least one of the transmitting or receiving ends of said transmission system and comprises in combination: a variable-capacitance diode having a capacitance controllable in response to the voltage of said base-band signal applied thereto, input means for supplying to said variable-capacitance diode said base-band signal, output means for deriving from said variable-capacitance diode a delay-compensated base-band signal, said variable-capacitance diode being connected in shunt between said input and output means and ground, a first resistor connected in series between said input means and the junction of said variable-capacitance diode with said output means, a second resistor connected in common to said variablecapacitance diode and said output means and in shunt to ground such that the envelope time delay is approximated by Cd (R1R2/R1 + R2) where Cd is the junction capacity of said variable-capacitance diode and R1 and R2 are the resistances of said first and second resistors, respectively, and bias means for supplying to said variable-capacitance diode a direct-current bias voltage so as to set the non-input capacitance of said variable-capacitance diode at a suitable value.
Claim 3
Dependent Claim
51 words
An equalizer as recited in claim 1, further comprising: a third resistor connected in series between said first resistor and said output means and a capacitor connected in parallel to said third resistor, said third resistor and capacitor being operative to improve the transmission characteristic of said equalizer in the base-band.
Claim 4
Dependent Claim
42 words
An equalizer as recited in claim 1, wherein said bias means comprises a large capacitance capacitor connected in series with said variable-capacitance diode and ground, and variable d.c. bias voltage source connected to the junction of said capacitor and said variable-capacitance diode.
Claim 5
Dependent Claim
39 words
An equalizer as recited in claim 1, further comprising: a low-pass filter connected in series between said first resistor and said output means, said low-pass filter being operative to improve the transmission characteristic of said equalizer in the base-band.
Claim 6
Dependent Claim
31 words
An equalizer as recited in claim 4, wherein said low-pass filter comprises the capacitance of said variable-capacitance diode and an inductor connected in series between said first resistor and said junction.
References Cited (Backward Citations)
US2430978A
Cited
US3422378A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-18 | 1978-05-20 | 1978-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-18 | 1982-05-20 | 1982-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-18 | 1986-05-20 | 1986-11-19 | $7700.00 | Window Closed / Lapsed |