We claim:
1. A communications acquisition method, which comprises:
correlating a binary-coded spread sequence arriving at a frequency f and having m bits with a locally generated spread sequence by phase-shifting a multiplicity of locally generated spread sequences with respect to the received spread sequence;
correlating the received spread sequence with a locally generated spread sequence at the frequency f;
storing the received spread sequence and processing the stored, received spread sequence at an oversampling rate of i*f, where i is an integer; and
splitting the stored, received spread sequence into i sections and carrying out the correlation in i steps.
2. The method according to claim 1, which further comprises:
shifting the received spread sequence bit by bit within k cycles in k section variants each having m bits at an oversampling rate of k*f, where k is an integer, by shifting a most significant bit of a section variant to a position of a least significant bit of a succeeding section variant;
after k cycles, replacing the least significant bit by a succeeding bit of the received spread sequence and repeating the shifting and replacing steps m1) times;
subdividing the locally generated spread sequence into k sections each having n bits, where n is an integer, and comparing each of these sections with a section variant of the received spread sequence within a cycle;
counting all matches and storing the count results; and
carrying out a maximum search over all the count results.
3. The method according to claim 2, wherein a number of sections of prescribed length is k32 and a chip length of the sections is n32.
4. A correlator for performing a communications acquisition, comprising:
a FIFO memory having a memory input and a memory output, said FIFO memory inputting and outputting content;
a shift register with feedback for holding a received signal sequence in serial form, said shift register being clocked at an oversampling rate and having register positions connected in parallel to said memory input for parallel storage of a plurality of shift register contents read out in succession, said memory output being connected in parallel with said register positions for parallel transfer of data to said shift register;
a further memory for holding reference signal sequences; and
a comparator for comparing the content of said FIFO memory with a content of said further memory at said oversampling rate;
the correlator programmed to perform the steps of:
correlating a binary-coded spread sequence arriving at a frequency f and having m bits with a locally generated spread sequence by phase-shifting a multiplicity of locally generated spread sequences with respect to the received spread sequence;
correlating the received spread sequence with a locally generated spread sequence at said frequency f;
storing the received spread sequence and processing the stored, received spread sequence at said oversampling rate equal to i*f, where i is an integer; and
splitting the stored, received spread sequence into i sections and carrying out the correlation in i steps.
5. The correlator according to claim 4, wherein said comparator has a comparator output, and including an adder comprising two-bit adders configured to form a cascaded interconnection, each of said two-bit adders having at least two inputs and an output, said output of each of said two-bit adders connected to one of said at least two inputs of a succeeding one of said two-bit adders, said adder connected to said comparator output and configured to add up logic values produced during bit-by-bit comparison for matching bit positions.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Apparatus for coating pipes comprising means for applying a sheet material to a pipe, means for heating the sheet material andor pipe and a releasably mounted canister housing a reel for supplying sheet material in the form of a tape which may be withdrawn from the canister.
2. Apparatus as clained in claim 1, wherein the means for heating is operative to heat the shet material andor pipe during application of the sheet material to the pipe.
3. Apparatus as claimed in either claim 1 or 2, wherein the means for heating includes means for directing hot air towards the pipe andor sheet material.
4. Apparatus as claimed in any preceding claim for applying sheet material in the form of a tape to a pipe in a helical pattern, including means for tensioning the tape as it is applied to the pipe and means for urging the tape onto the pipe.
5. Apparatus as claimed in claim 4, comprising a stator for mounting on a pipe and a rotor, rotatably mounted on the stator for rotation around the periphery of the pipe.
6. Apparatus as claimed in claim 5 comprising drive means to move at least part of the rotor longitudinally along the pipe.
7. Apparatus as claimed in claim 6, wherein the drive means is driven by relative movement of the rotor and stator.
8. Apparatus as claimed in claim 7, wherein the drive means can be disengaged to allow movement of the at least part of the rotor longitudinally along the pipe independently of relative rotation of the stator and rotor.
9. Apparatus as claimed in any of claims 5 to 8, wherein the means for heating is mounted on the rotor.
10. Apparatus as claimed in any of claims 6 to 9, wherein the rotor comprises means for releasably supporting a reel of tape.
11. Apparatus as claimed in any of claims 5 to 10, wherein the stator andor rotor comprise rings formed from two or more pivotally connected components.
12. Apparatus as claimed in any preceding claim, wherein the canister includes a means for heating operative to heat a reel of tape disposed therein.
13. A method for coating a pipe by application of a sheet material including the steps of preheating the sheet material using a first heating means prior to application of the sheet material to the pipe, and heating the pipe andor sheet material using a second heating means during the application of the sheet material to the pipe.
14. A method as claimed in claim 13 including the step of directing hot air towards the pipe andor sheet material during the application of sheet to the pipe.
15. A method as claimed in either claim 13 or 14, wherein the sheet material comprises a tape provided on a reel.
16. A method as claimed in claim 15, wherein the reel is disposed in a canister.
17. A method as claimed in claim 16, wherein the first heating means is comprised in the canister.
18. A method as claimed in any of claims 13 to 16, wherein the sheet material is preheated in an oven.
19. A method as claimed in any of claims 13 to 18 performed using apparatus as claimed in any of claims 1 to 12.