GB1395496A - Voice frequency transmission circuit - Google Patents

Voice frequency transmission circuit

Info

Publication number
GB1395496A
GB1395496A GB5143774A GB5143774A GB1395496A GB 1395496 A GB1395496 A GB 1395496A GB 5143774 A GB5143774 A GB 5143774A GB 5143774 A GB5143774 A GB 5143774A GB 1395496 A GB1395496 A GB 1395496A
Authority
GB
United Kingdom
Prior art keywords
voice frequency
signal
envelope
transmission circuit
frequency signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB5143774A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Post Office
Original Assignee
Post Office
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Post Office filed Critical Post Office
Priority to GB5143774A priority Critical patent/GB1395496A/en
Priority claimed from GB3069271A external-priority patent/GB1395495A/en
Publication of GB1395496A publication Critical patent/GB1395496A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/42—Systems providing special services or facilities to subscribers
    • H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other

Abstract

1395496 Directional switching POST OFFICE 28 June 1972 [30 June 1971] 51437/74 Divided out of 1395495 Heading H4R A transmission circuit produces a signal representing the envelope of a voice frequency signal applied to the input LT2 and combines the envelope signal with the voice frequency signal so that the combined signal is unidirectional (i.e. unilateralized). The envelope signal is produced by a rectifying means including an inverting amplifier A1 receiving the voice frequency signal through a resistor R1 and having an output which is coupled to the amplifier through two feedback circuits, one including a rectifier D1 in series with a resistor R7 and the second including a resistor R6 and a rectifier D2. The output of the rectifying means is a substantially undistorted representation of the envelope of the voice frequency signal. The transmission circuit is applied to a telephone conference amplifier circuit (see Specification 1,395,495).
GB5143774A 1971-06-30 1971-06-30 Voice frequency transmission circuit Expired GB1395496A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB5143774A GB1395496A (en) 1971-06-30 1971-06-30 Voice frequency transmission circuit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB3069271A GB1395495A (en) 1971-06-30 1971-06-30 Telephone conference amplifier
GB5143774A GB1395496A (en) 1971-06-30 1971-06-30 Voice frequency transmission circuit

Publications (1)

Publication Number Publication Date
GB1395496A true GB1395496A (en) 1975-05-29

Family

ID=26260556

Family Applications (1)

Application Number Title Priority Date Filing Date
GB5143774A Expired GB1395496A (en) 1971-06-30 1971-06-30 Voice frequency transmission circuit

Country Status (1)

Country Link
GB (1) GB1395496A (en)

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Legal Events

Date Code Title Description
PS Patent sealed
435 Patent endorsed 'licences of right' on the date specified (sect. 35/1949)
PCNP Patent ceased through non-payment of renewal fee