Method and circuit arrangement for implementing inter-system synchronization in a multimode device

A radio telecommunication device for communicating with a first telecommunication system and a second telecommunication system, comprising a first radio transceiver and a second radio transceiver and within each radio transceiver for generating a frame time counter input clock, comprising:

• a first counter responsive to the frame time counter input clock generated in the first radio transceiver,
• a second counter responsive to the frame time counter input clock generated in the second radio transceiver, wherein the frame time counter input clock generated in the first radio transceiver is isolated from and not common to the frame time counter input clock generated in the second radio transceiver,
• first snapshot storage means responsive to a first triggering signal for storing the value of said first counter that coincides with the reception of said first triggering signal, and
• a processor for reading the stored value of said first counter and for timing an operation performed by the processor so that the timing of the operation in relation to the timing of the first telecommunication system is known.

A method of synchronizing a timing between a timing of a first telecommunication system and a timing of a second telecommunication system comprising:

• updating a first counter value at a pace determined by the first telecommunication system;
• updating a second counter value at a pace determined by the second telecommunication system wherein the pace determined by the first telecommunication system is not related to the pace determined by the second telecommunication system;
• at a first time instant in response to a common triggering signal, storing a current first and a current second counter value;
• at a subsequent time instant reading the stored current first and second counter values;
• and
• using the read stored current first and second counter values to time an operation of a processor so that the timing of the operation in relation to the timing of the first telecommunication system is known.

A method of arranging a timing in a single telecommunication device operating in at least two mutually separate telecommunication systems comprising:

• determining a timing of an operation in a first telecommunication system having a first time base by regularly updating a first counter value at a pace determined by the first telecommunication system, the pace being related to a time base of the first telecommunication system, and at a first time instant reading the current first counter value and storing the read first counter value into a storage location different from the counter itself;
• determining a timing of an operation in a second telecommunication system having a second time base mutually exclusive from the first time base by regularly updating a second counter value at a pace determined by the second telecommunication system, the pace being related to a time base of the second telecommunication system, the time base of the first telecommunication system being different than the time base of the second telecommunication system, at a second, later time instant reading the stored read first counter value;
• and
• the second telecommunication system using the determined timing in the first telecommunication system to time an operation in the single telecommunication device by using the counter value read at the second, later time instant to time an operation performed by a processor so that the timing of the operation in relation to the timing of the first telecommunication system is known.