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Publication of BE693006ApublicationCriticalpatent/BE693006A/xx
H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
H01F29/00—Variable transformers or inductances not covered by group H01F21/00
H01F29/14—Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias
H01F29/146—Constructional details
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04M—TELEPHONIC COMMUNICATION
H04M3/00—Automatic or semi-automatic exchanges
H04M3/22—Arrangements for supervision, monitoring or testing
H04M3/2272—Subscriber line supervision circuits, e.g. call detection circuits
H—ELECTRICITY
H01—ELECTRIC ELEMENTS
H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
H01F29/00—Variable transformers or inductances not covered by group H01F21/00
H01F29/14—Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias
H01F2029/143—Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias with control winding for generating magnetic bias