Precision time of day counter
AssigneeE-Systems, Inc.
InventorsAlbert D. Scalo, Bruce F. Karaffa
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Abstract
A very high speed counter system of operating at frequencies of up to around 800 MHz provides timing measurements with accuracies on the order of (1/f) seconds where f is the frequency of operation. The least significant bit of the counter operates at the given frequency of a first clock signal while the other higher order bits operate at a second clock signal where the second clock signal is one-half the frequency of the first clock signal and is inverted. Carry lookahead circuits connected between stages of the second counter operate in conjunction with the clocking scheme to produce a high speed and accurate counter.
Claims34
A counting system comprising:
- a counter including a first stage having at least one register defining a bit position and a plurality of successive stages each having at least one register defining a bit position, said first stage responding to a first clock signal having periodic clock pulses of a first predetermined frequency and said successive stages responding to a second clock signal having periodic clock pulses of a second predetermined frequency, the second predetermined frequency having a different frequency value than the first predetermined frequency;
- a circuit for generating lookahead carry signals applied to at least one of the successive stages of the counter;
- and
- a clock input for supplying the first and second clock signals to the counter.
A counting system comprising:
- a first register defining a least significant bit, said first register responding to a first clock signal having periodic clock pulses of a first predetermined frequency;
- a plurality of successive counting stages each having at least one register, each of said registers defining a bit position, said plurality of successive stages responding to a second clock signal having periodic clock pulses of a second predetermined frequency, the second predetermined frequency having a different frequency value than the first predetermined frequency;
- and
- a circuit for generating lookahead catty signals applied to each of the plurality of successive stages.
A precision time of day counting system comprising:
- a first stage comprising at least one register defining a bit, said first stage responding to a first clock signal having periodic pulses;
- a second stage comprising a plurality of subordinate counters interconnected to receive a plurality of carry signals, each of said subordinate counters having at least one register defining a bit, said second stage responding to a second clock signal having periodic clock pulses;
- at least one circuit for generating and supplying the carry signals to the subordinate counters;
- a first latch register for latching the least significant bit of the first stage in response to a timing signal;
- a second latch register for latching the bits of the second stage in response to the timing signal;
- and
- a shift register for serially outputting the bits in the first and second latch register.
A counting system comprising:
- a plurality of stages each having at least one register defining a bit position, said stages responding to a clock signal having periodic pulses of a predetermined frequency;
- a circuit for generating lookahead carry signals applied to at least one of the plurality of stages;
- a latch register for latching the bits of each of the stages in response to the timing signals;
- and
- a shift register for serially outputting the bits of the latch register.
Dependencies are inferred from the claim text.