Efficient processing and detection of balanced codes

• US 9,203,402 B1
• Filed: 11/25/2013
• Issued: 12/01/2015
• Est. Priority Date: 05/20/2010
• Status: Active Grant

• Current Assignee: Kandou Labs, SA
• Original Assignee: Kandou Labs, SA
• Inventors: Tajalli, Armin, Cronie, Harm, Shokrollahi, Amin
• Primary Examiner(s): LAUTURE, JOSEPH J
• Application Number:
  US14/089,577
• Time in Patent Office: 736 Days
• Field of Search: 341/58, 341/95, 375/295, 375/296, 375/259, 375/134, 714/776, 714/18, 714/787, 714/755
• US Class Current: 1/1
• CPC Class Codes: G11B 20/1426 conversion to or from block codes or representations thereof
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor
• CPC Class Codes: H03M 13/2957 Turbo codes and decoding
• CPC Class Codes: H03M 5/14 Code representation, e.g. transition, for a given bit cell depending on the information in one or more adjacent bit cells, e.g. delay modulation code, double density code
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0048 in conjunction with detection of multiuser or interfering signals, e.g. iteration between CDMA or MIMO detector and FEC decoder for spatial equalizer H04L25/03286
• CPC Class Codes: H04L 1/0053 specially adapted for power saving
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0059 Convolutional codes

Abstract

Circuits that are matched to balanced codes may recover transmitted information in a noise resilient and power efficient manner. Circuit components for processing a balanced code may include one or more of: matched amplification of the signals representing the balanced code, matched equalization and/or filtering on the signals representing the balanced code, matched non-linear filtering on the signaling representing the balanced code to detect the presence of particular symbols and matched latching of the signals representing the balanced code. Such matched circuits and circuit components may be achieved at least in part by incorporating suitable common circuit nodes and/or a single energy source into circuit topologies.

Claims

1. An apparatus comprising:

a plurality of input lines configured to receive a set of signals associated with a balanced vector signaling codeword, wherein each signal of the set of signals are associated with a codeword element selected from the group of +1, 0, and −

1;

a plurality of receiver branches, each receiver branch having a load resistor and a transistor, and each transistor being coupled to a common node that is common to all receiver branches of the plurality of receiver branches, and having a gate input node connected to a respective input line of the plurality of input lines, and each transistor further configured to operate in a non-linear mode such that only input signals associated with a +1 codeword element causes the respective transistor to conduct current;

a current source coupled to the common node and configured to draw tail bias currents through ones of the plurality of receiver branches having input signals associated with a +1 codeword element; and

,

a plurality of output lines configured to provide a set of output signals identifying receiver branches connected to respective input lines having signals associated with +1 codeword elements.

2. The apparatus of claim 1 wherein the transistors are NMOS transistors.

3. An apparatus comprising:

a plurality of input lines configured to receive a set of signals associated with a balanced vector signaling codeword, wherein each signal of the set of signals are associated with a codeword element selected from the group of +1, 0, and −

1;

a plurality of receiver branches, each receiver branch having a load resistor and a transistor, and each transistor being coupled to a common node that is common to all receiver branches of the plurality of receiver branches, and having a gate input node connected to a respective input line of the plurality of input lines, and each transistor further configured to operate in a non-linear mode such that only input signals associated with a −

1 codeword element causes the respective transistor to conduct current;

a current source coupled to the common node and configured to draw tail bias currents through ones of the plurality of receiver branches having input signals associated with a −

1 codeword element; and

,

a plurality of output lines configured to provide a set of output signals identifying receiver branches connected to respective input lines having signals associated with −

1 codeword elements.

4. The apparatus of claim 3 wherein the transistors are PMOS transistors.

5. An apparatus comprising:

a plurality of input lines configured to receive a set of signals associated with a balanced vector signaling codeword, wherein each signal of the set of signals are associated with a codeword element selected from the group of +1, 0, and −

1;

a first common node having a current sink and a second common node having a current source;

a plurality of receiver branches, each receiver branch coupled between the first common node and the second common node;

each receiver branch having a load resistor, a first transistor, and a second transistor, wherein the first transistor and second transistor each having gate input nodes connected to a respective input line of the plurality of input lines, and the first transistor and second transistor further configured to operate in a non-linear mode such that only input signals associated with a +1 codeword element conduct current in the first transistor and only input signals associated with a −

1 codeword element conduct current in the second transistor; and

,

a plurality of output lines configured to provide a set of output signals that (i) identify receiver branches connected to respective input lines having signals associated with +1 codeword elements in accordance with a first voltage drop across the branch'"'"'s respective load resistor and (ii) identify receiver branches connected to respective input lines having signals associated with −

1 codeword elements in accordance with a second voltage drop across the branch'"'"'s respective load resistor and (iii) identify receiver branches connected to respective input lines having signals associated with 0 codeword elements in accordance with substantially no voltage drop across the branch'"'"'s respective load resistor.

6. The apparatus of claim 5 wherein the load resistor of each branch is connected to a third common node having an intermediate voltage value.

7. The apparatus of claim 6 wherein the first voltage drop causes the associated output line to have a voltage greater than the common node, and wherein the second voltage drop causes the associated output line to have a voltage less than the common node.

8. An apparatus for processing signals corresponding to balanced code signals, comprising:

a set of controlled sources in a configuration with at least one common node;

at least one current source constraining power supply current flow into or out of the least one common node;

inputs to the controlled sources comprising two or more values representing the code word of a balanced code; and

an output result derived from the current provided by each controlled source.

9. The apparatus of claim 8, wherein the controlled sources are MOS transistors.

10. The apparatus of claim 9, further comprising complimentary MOS transistors gating current flow to and current flow from each of the controlled sources based on a timing clock signal.

11. The apparatus of claim 10, wherein each output result is obtained from a corresponding CMOS inverter attached to a corresponding controlled current source.

12. The apparatus of claim 11, wherein the pulse width or transition slew rate of each output result is determined by the capacitance at the input node of its corresponding CMOS inverter and the proportion of the predetermined current flowing through its corresponding controlled current source.

13. The apparatus of claim 12, wherein each output result also comprises a balanced code encoded in a time dimension.

14. An apparatus for processing signals, comprising:

a first pair of complimentary p and n channel MOS transistors in a series configuration;

at least one of a supply current source and a sink current source controlling current through and setting the operating point of the first pair of transistors;

a gate input node corresponding to the gates of the first pair of transistors;

a second pair of complimentary p and n channel MOS transistors in a series configuration in the reverse order as those of the first pair of complimentary transistors, the common node between the transistors of the first pair being connected directly to the common node between the transistors of the second pair, the gates of the second pair being connected via capacitive coupling, and a resistive connection to one or more DC bias voltage sources configured to provide a transistor DC bias; and

,

an output signal node at the common node between the transistors of the second pair.

15. A circuit for processing signals comprising:

series connected complimentary p-channel and n-channel MOS transistors,

an input signal circuit comprising a parallel resistor and capacitor network configured to provide an input to each of the series connected transistors;

a fixed current sink connected to a source node of the n-channel MOS transistor;

a fixed current source connected to a drain node of the p-channel MOS transistor;

at least one output node corresponding to a node selected from the n-channel source node and the p-channel drain node.

16. The circuit of claim 15, wherein the input signal circuit is configured to provide a frequency dependent input signal.

17. The circuit of claim 16, wherein the input signal circuit includes a plurality of capacitances to provide a boost in gain for high frequency input signals.

18. The circuit of claim 15 wherein the input signal circuit is configured to (i) shift a DC level at a gate of the n-channel MOS transistor closer to a positive supply voltage and (ii) shift a DC level at a gate of the p-channel MOS transistor closer to a negative supply voltage.