US 4,061,970 A · Transmission system and repeater stations therefor

Abstract

A transmission system in which wide band electrical signals are transmitted along a transmission line has repeater stations located at intervals along the line for boosting and equalizing the signals. Each repeater station has an equalizer having a frequency response characteristic which generally complements that of the section of the transmission line which it covers. The frequency response characteristic of the equalizer is capable of adjustment to match the section of transmission line which feeds it. The adjustment required will vary when the section of transmission line feeding it has a length differing from that of a norm and where the line is subject to temperature changes. The repeater station incorporates a feedback chain which senses a pilot transmitted along the section of transmission line and responds to the monitored level of the pilot signal to automatically adjust the characteristic of the equalizer until it matches that of the transmission line section in question. This avoids the necessity of manually adjusting the equalizer of the repeater station at each installation.

Claims11

Dependent claims

A repeater station for cable transmission of high frequency signals covering a predetermined wide band of frequencies and including a reference component having a predetermined frequency, said station comprising:

an equalizer including a resistor T pad having two transverse resistive members and one leg member, a series resonant circuit connected in parallel across both transverse resistive members of said T, and a parallel resonant circuit connected in series with said leg member of said T,
ends of said transverse resistive members defining input and output of said equalizer, while an end of said leg member is coupled to ground,
said two resonant circuits having an adjustment means for adjusting the resonant frequency of each, and
automatic control means having an input coupled to said equalizer output and output coupled to said adjusting means, said automatic control means responsive to a level of said reference cmmponent of said equalizer output to adjust the resonant frequencies of said two resonant circuits thereof and a corresponding substantially common frequency in a sense to maintain substantially constant said level of said reference component, whereby a signal level/frequency response slope of said equalizer is varied to correct for increasing losses in said transmitting cable of higher frequencies in said predetermined wide band frequencies.

1 more element

In a transmission system including a transmission line having a predetermined signal level/frequency characteristic for electrical signals having a predetermined bandwidth, a repeater station for equalizing the said electrical signals, the station comprising:

an equalizer having a signal level/frequency characteristic which generally complements that of the transmission line and a control input for adjusting the said characteristic of said equalizer,
feedback means for monitoring the output of said equalizer and responsive to a reference signal therein which is processed through said equalizer and has a frequency equal to an upper frequency in said predetermined bandwidth,
said feedback means having an output connected to said control input of said equalizer and being operative to control the slope of the equalizer characteristic in a sense to maintain the monitored level of the reference signal at a predetermined level in order to compensate the characteristic of the equalizer for variations in the characteristic of said transmission line due to changes in temperature and line length over a limited range,
said equalizer including a resistive T pad having two transverse resistive members and one leg member, a series resonant circuit connected in parallel acrosss both transverse resistive members of said T, and a parallel resonant circuit connected in series within said leg member of said T,
ends of said transverse resistive members forming input and output of said equalizer and an end of said leg member coupled to ground,
said two resonant circuits including adjustment means for adjusting the resonant frequency of each and coupled to said control input of said equalizer.

3 more elements

Dependencies are inferred from the claim text.

Transmission system and repeater stations therefor

Life of this patent

Transmission system and repeater stations therefor

Life of this patent

Abstract

Claims11