| 摘要 |
A pulse position demodulator circuit is provided which finds particular use in instrument landing systems, but which has general utility. The system responds to a pulse signal in which successive pulse pairs are position modulated in accordance with an incremental modulating signal, and it provides digital outputs which are precise measurements of the time spacing between the pulses of each individual pair, the digital outputs constituting a representation of the modulating incremental signal. The system includes a network for generating a multiplicity of clock signals having different phase relationships. A particular clock is selected by the lead pulse of each received pulse pair to enable a correct digital output to be produced by the system even though the second pulse of the pair may be received earlier or later than a particular reference time. This reduces the resolution requirements of the system without affecting its accuracy, thereby permitting a low speed shift register to be used of the order of one-fourth the length of the shift register which would be required in an equivalent prior art system.
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