GB1479166A - Voice frequency receiver - Google Patents

Voice frequency receiver

Info

Publication number
GB1479166A
GB1479166A GB4674574A GB4674574A GB1479166A GB 1479166 A GB1479166 A GB 1479166A GB 4674574 A GB4674574 A GB 4674574A GB 4674574 A GB4674574 A GB 4674574A GB 1479166 A GB1479166 A GB 1479166A
Authority
GB
United Kingdom
Prior art keywords
rate
voltage
change
receiver
envelope
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
GB4674574A
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.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
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 Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB4674574A priority Critical patent/GB1479166A/en
Priority to IE224575A priority patent/IE41753B1/en
Publication of GB1479166A publication Critical patent/GB1479166A/en
Priority to HK5978A priority patent/HK5978A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/46—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

1479166 Voice frequency receivers STADABD TELEPHONES & CABLES Ltd 28 Oct 1975 [29 Oct 1974] 46745/74 Heading H4R During a persistence check in a V.F. receiver the rate of change of the envelope of an incoming tone is monitored and if the rate of change exceeds a predetermined limit the output of the receiver is inhibited. In a first embodiment the rate of change detection circuit Fig. 3 is applied to a known automatic gain control arrangement connected between a tone input and the frequency selective circuits, the rate of change detector monitoring the negative feedback voltage derived from the envelope of the received signal. In Fig. 3, the network C-R1 is such that a suitable voltage appears across R1 for a given rate of change of input voltage, voltage comparator 2 responding to a positive voltage across R1 exceeding a threshold level to inhibit the gate G and comparator 1 similarly responding to a negative voltage. The circuit of Fig. 3 may also be applied to a receiving arrangement as illustrated in Fig. 1 (not shown).
GB4674574A 1974-10-29 1974-10-29 Voice frequency receiver Expired GB1479166A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB4674574A GB1479166A (en) 1974-10-29 1974-10-29 Voice frequency receiver
IE224575A IE41753B1 (en) 1974-10-29 1975-10-15 Improvements in or relating to voice frequency receiver
HK5978A HK5978A (en) 1974-10-29 1978-01-26 Improvements in or relating to voice frequency receiver

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4674574A GB1479166A (en) 1974-10-29 1974-10-29 Voice frequency receiver

Publications (1)

Publication Number Publication Date
GB1479166A true GB1479166A (en) 1977-07-06

Family

ID=10442428

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4674574A Expired GB1479166A (en) 1974-10-29 1974-10-29 Voice frequency receiver

Country Status (3)

Country Link
GB (1) GB1479166A (en)
HK (1) HK5978A (en)
IE (1) IE41753B1 (en)

Also Published As

Publication number Publication date
IE41753L (en) 1976-04-29
HK5978A (en) 1978-02-03
IE41753B1 (en) 1980-03-12

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee