Randomized-clock circuit

• US 4,571,556 A
• Filed: 07/28/1983
• Issued: 02/18/1986
• Est. Priority Date: 07/28/1983
• Status: Expired due to Fees

• Current Assignee: MI Medical & Scientific Instruments Incorporated
• Original Assignee: MI Medical & Scientific Instruments Incorporated
• Inventors: Gnerlich, Hans R., Zimmermann, Kuno P.
• Primary Examiner(s): Grimm, Siegfried H.
• Application Number:
  US06/517,969
• Time in Patent Office: 936 Days
• Field of Search: 331/78, 364/717, 128/420 A, 128/421, 128/422, 128/423 W
• US Class Current: 331/78
• CPC Class Codes: A61N 1/08 Arrangements or circuits for monitoring, protecting, controlling or indicating for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925
• CPC Class Codes: A61N 1/36014 External stimulators, e.g. with patch electrodes external pacemakers A61N1/3625
• CPC Class Codes: A61N 1/36021 for treatment of pain
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators

Abstract

A randomized-clock circuit produces a random pulse train of predetermined sequence length and truncated exponential distribution of the gaps between pulses by multiplying a periodic clock signal with the output signal of a maximal length pseudorandom sequence generator which is clocked by the periodic clock signal. Control circuits monitor the maximal length pseudorandom pulse generator to start or stop random pulse sequences; random sequences are repeatable and a circuit to preset their starting point is provided. Cascading or connecting randomized-clock circuits in XOR, OR or AND gates is used to change the parameters of the exponential distribution function of the gaps. Pulse width and amplitude adjusting circuits allow interfacing of the randomized-clock circuit (a) with trigger inputs of medical and scientific pulse generators and (b) with electrodes connected to primates when the randomized-clock circuit is used as a nerve and/or muscle stimulator.

Claims

1. A randomized-clock circuit comprising a maximal length pseudorandom sequence generator (MLPSG), a periodic circuit clock, a multiplier, a circuit to start a pseudorandom sequence and a pulse width and amplitude adjusting circuit, the multiplier, multiplying the output of the MLPSG with the output of the periodic circuit clock, is providing at its output a random pulse train of known sequence length and gap statistics with truncated exponential distribution, the MLPSG comprises an N-stage shift register, selected stages of which are mod-2 fed back to the input of the MLPSG, wherein the feedback satisfies a primitive, irreducible polynominal of degree N, the circuit to start a psueudorandom sequence is sending a starting pulse to the MLPSG if the MLPSG is in a state in which it does not produce pulse sequences, the pulse width and amplitude adjusting circuit is regulating the width, amplitude, shape and power of the pulses of the random sequence.

2. A randomized-clock circuit, as recited in claim 1, wherein a circuit to preset the maximal length pseudorandom sequence generator to a specific starting value is provided and a monitor and control circuit is provided to selectively (a) stop the circuit clock and (b) indicate when a certain combination of high and low states of the shift register stages is detected.

3. A randomized-clock circuit, as recited in claim 1, wherein the output of the pulse width and amplitude adjusting circuit is making contact with a primate body through electrodes for nerve and muscle stimulation.

4. A cascaded randomized-clock circuit, wherein a randomized-clock circuit is the circuit clock for n, n=1, 2, . . . , cascaded clock randomizers, said randomized-clock circuit comprising a maximal length pseudorandom sequence generator (MLPSG), a periodic circuit clock, a multiplier, a circuit to start a pseudorandom sequence and a pulse width and amplitude adjusting circuit, the multiplier, multiplying the output of the MLPSG with the output of the periodic circuit clock, is providing at its output a random pulse train of known sequence length and gap statistics with truncated exponential distribution, the MLPSG comprises an N-stage shift register, selected stages of which are mod-2 fed back to the input of the MLPSG, wherein the feedback satisfied a primitive, irreducible polynomial of degree N, the circuit to start a pseudorandom sequence is sending a starting pulse to the MLPSG is in a state in which it does not produce pulse sequences, the pulse width and amplitude adjusting circuit is regulating the width, amplitude, shape and power of the pulses of the random sequence.

5. A cascaded randomized-clock circuit, as recited in claim 4, wherein a circuit to preset the maximal length pseudorandom sequence generator to a specific starting value is provided and a monitor and control circuit is provided to selectively (a) stop the circuit clock and (b) indicate when a certain combination of high and low states of the shift register stages is detected.

6. A cascaded randomized-clock circuit, as recited in claim 4, wherein the output of the pulse width and amplitude adjusting circuit of the cascade'"'"'s last clock randomizer makes contact with a primate body through electrodes for nerve and muscle stimulation.

7. A random pulse generator comprising k randomized-clock circuits with periodic clock frequencies f_k =f_k-1 +Δ

f_k, f_k >

>

Δ

f_k, where k=2, 3, . . . , and the randomized-clock circuit outputs are combined in one of a XOR, OR and AND gate, said randomized-clock circuit comprising a maximal length pseudorandom sequence generator (MLPSG), a periodic circuit clock, a multiplier, a circuit to start a pseudorandom sequence and a pulse width and amplitude adjusting circuit, the multiplier, multiplying the output of the MLPSG with the output of the periodic circuit clock, is providing at its output a random pulse train of known sequence length and gap statistics with truncated exponential distribution, the MLPSG comprises an N-stage shift register, selected stages of which are mod-2 fed back to the input of the MLPSG, wherein the feedback satisfies a primitive, irreducible polynomial of degree N, the circuit to start a pseudorandom sequence is sending a starting pulse to the MLPSG if the MLPSG is in a state in which it does not produce pulse sequences, the pulse width and amplitude adjusting circuit is regulating the width, amplitude, shape, and power of the pulses of the random sequence.

8. A random pulse generator, as recited in claim 7, wherein circuits to preset the maximal length pseudorandom sequence generators to a specific starting value are provided.

9. A random pulse generator, as recited in claim 7, wherein the output of the logic gate, after being amplitude and pulse width adjusted, is making contact with a primate body through electrodes for nerve and muscle stimulation.