Analog pseudo random bit sequence generator

• US 8,156,167 B2
• Filed: 05/23/2007
• Issued: 04/10/2012
• Est. Priority Date: 05/23/2007
• Status: Expired due to Fees

• Current Assignee: Anritsu Corporation
• Original Assignee: Anritsu Corporation
• Inventors: Bradley, Donald Anthony
• Primary Examiner(s): Ngo, Chuong D
• Application Number:
  US11/752,739
• Publication Number:
  US 20080290912A1
• Time in Patent Office: 1,784 Days
• Field of Search: 708/250, 708/252
• US Class Current: 708/250
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators

Abstract

A Pseudo Random Bit Sequence (PRBS) generator is provided with components to enable operation at very high microwave frequencies with inexpensive components. The PRBS generator initially replaces the D flip-flops of a conventional PRBS generator with delay lines connected in a similar manner. Further, an exclusive OR (EXOR) gate used in a conventional device is replaced in one embodiment by a mixer and amplifier. In another embodiment, the EXOR gate is replaced by a Gilbert Cell. In some embodiments, complementary outputs of an EXOR gate are connected to separate delay lines to reduce components needed for the PRBS generator.

Claims

1. A pseudo random bit sequence (PRBS) generator comprising:

an exclusive OR (EXOR) circuit having an output providing an output of the PRBS generator;

a first delay line having an input connected to an output of the EXOR circuit, and an output connected to a first input of the EXOR circuit; and

a second delay line having an input connected to an output of the EXOR circuit, and an output connected to a second input of the EXOR circuit;

wherein the EXOR circuit comprises;

a mixer having a LO input connected to the output of the first delay line, an RF input connected to the output of the second delay line, and an IF output; and

an amplifier having an input connected to the IF output of the mixer and an output providing the output of the EXOR circuit; and

wherein the mixer of the EXOR circuit comprises;

a differential amplifier having an input forming the RF input of the mixer and first and second differential outputs;

a first diode having an anode terminal connected to the first differential output and a cathode terminal forming the LO input of the mixer;

a second diode having a cathode terminal connected to the second differential output and an anode terminal connected to the LO input;

a third diode having an anode terminal connected to the LO input and a cathode terminal connected to the IF output of the mixer; and

a fourth diode having a cathode terminal connected to the input and an anode terminal connected to the IF output.

2. The PRBS generator of claim 1,

wherein the output of the EXOR circuit is connected to each of the first delay line, the second delay line and the output of the PRBS generator through a separate output of a three way splitter.

3. The PRBS generator of claim 1, wherein the first delay line and the second delay line comprise different lengths of coaxial cable.

4. The PRBS generator of claim 1, wherein the first delay line and the second delay line comprise different lengths traces on a PC board.

5. A pseudo random bit sequence (PRBS) generator comprising:

an exclusive OR (EXOR) circuit having an output providing an output of the PRBS generator;

a first delay line having an input connected to an output of the EXOR circuit, and an output connected to a first input of the EXOR circuit; and

a second delay line having an input connected to an output of the EXOR circuit, and an output connected to a second input of the EXOR circuit,

wherein the EXOR circuit comprises a Gilbert Cell that comprises;

first and second differential amplifiers connected to provide first inputs x and x_b and outputs o and o_b for the Gilbert Cell, wherein the x_b input is connected to ground, the x input provides a first input of the EXOR circuit and the o_b output provides the output of the EXOR circuit; and

a third differential amplifier connected to provide second inputs y and y_b for the Gilbert Cell, wherein the y_b input is connected to ground and the y input provides a second input of the EXOR circuit.

6. A pseudo random bit sequence (PRBS) generator comprising:

an exclusive OR (EXOR) circuit having an output providing an output of the PRBS generator;

a first delay line having an input connected to an output of the EXOR circuit, and an output connected to a first input of the EXOR circuit; and

a second delay line having an input connected to an output of the first delay line and an output connected to a second input of the EXOR circuit;

wherein the EXOR gate comprises;

a mixer having a LO input connected to the output of the first delay line, an RF input connected to the output of the second delay line, and an IF output; and

an amplifier having an input connected to the IF output of the mixer and an output providing the output EXOR gate, and

wherein the mixer comprises a diode switch comprising;

a differential amplifier having an input forming the RF input of the mixer and first and second differential outputs;

a first diode having an anode terminal connected to the first differential output and a cathode terminal forming the LO input of the mixer;

a second diode having a cathode terminal connected to the second differential output and an anode terminal connected to the LO input;

a third diode having an anode terminal connected to the LO input and a cathode terminal connected to the IF output of the mixer; and

a fourth diode having a cathode terminal connected to the input and an anode terminal connected to the IF output.

7. A pseudo random bit sequence (PRBS) generator comprising:

an exclusive OR (EXOR) circuit having a first output and a second output complementary to the first;

a first delay line having an input connected to the first output of the EXOR circuit, and an output connected to a first input of the EXOR circuit; and

a second delay line having an input connected to the second complementary output of the EXOR circuit, and an output connected to a second input of the EXOR circuit

wherein the EXOR circuit comprises a Gilbert Cell, wherein the Gilbert Cell comprises;

first and second differential amplifiers connected to provide first inputs x and x_b and outputs o and o_b for the Gilbert Cell, wherein the x_b input is connected to ground, the x input provides a first input of the EXOR gate and the o_b output provides the first output of the EXOR gate, and the o output provides the second output of the EXOR gate; and

a third differential amplifier connected to provide second inputs y and y_b for the Gilbert Cell, wherein the y_b input is connected to ground and the y input provides a second input of the EXOR gate.