Systems and methods for communicating high speed signals in a communication device

Patent metadata

Field	Value
Publication number	US-9891638-B2
Application number	US-201514933771-A
Country	US
Kind code	B2
Filing date	Nov 5, 2015
Priority date	Nov 5, 2015
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A coupling module can be used to communicate high speed signals between an optical transceiver and a processing module of an optical communication device, such as an optical line termination (OLT) or an optical network unit (ONU). The coupling module can adjust the DC offset voltage level of the signal output by the optical transceiver to the DC offset voltage level required by the processing module. In addition, the coupling module splits the output signal from the optical transceiver and passes the signal to both a high pass filter and a low pass filter that are connected in parallel. The outputs of the high pass filter and the low pass filter are then combined and provided to the processing module. The high pass filter and the low pass filter can be configured such that all frequencies of the signal from the optical transceiver are provided to the processing module.

First claim

What is claimed is:

1. A coupling module comprising:
an input connection connected to a first input circuit to receive an input signal having a first DC offset voltage from the first input circuit;
a high pass filter connected to the input connection for receiving the input signal from the input connection, the high pass filter configured to filter the input signal and output a first filtered signal including signal frequencies greater than a first predetermined frequency;
a low pass filter connected to the input connection in parallel with the high pass filter for receiving the input signal from the input connection, the low pass filter configured to filter the input signal and output a second filtered signal including signal frequencies less than a second predetermined frequency, the low pass filter configured to adjust the first DC offset voltage of the input signal to provide a second DC offset voltage to the second filtered signal, wherein the second DC offset voltage is different from the first DC offset voltage; and
an output connection connected to the high pass filter and the low pass filter, the output connection for receiving the first filtered signal from the high pass filter and the second filtered signal from the low pass filter, the output connection configured to combine the first filtered signal and the second filtered signal to form a combined signal and provide the combined signal to a first output circuit,
wherein the second DC offset voltage of the second filtered signal corresponds to a DC offset voltage acceptable to the first output circuit.

2. The coupling module of claim 1 , wherein:
the high pass filter comprises a capacitor having a capacitance, and wherein the capacitance of the capacitor is used to establish the first predetermined frequency; and
the low pass filter comprises an operational amplifier connected in series with the input connection, the operational amplifier configured to provide the second DC offset voltage to the second filtered signal.

3. The coupling module of claim 2 , wherein the low pass filter further comprises:
a second output circuit connected to an output of the operational amplifier;
a feedback circuit connected between the output of the operational amplifier and an inverting input of the operational amplifier; and
a second input circuit connected to a non-inverting input of the operational amplifier,
wherein at least one of the second input circuit and the second output circuit is used to establish the second predetermined frequency.

4. The coupling module of claim 1 , wherein the second DC offset voltage corresponds to a required DC offset voltage of the first output circuit.

5. The coupling module of claim 1 , wherein the first filtered signal overlaps with the second filtered signal for a predetermined frequency range.

6. A coupling module comprising:
an input connection connected to a first input circuit to receive an input signal from the first input circuit;
a high pass filter connected to the input connection for receiving the input signal from the input connection, the high pass filter configured to filter the input signal and output a first filtered signal including signal frequencies greater than a first predetermined frequency, the high pass filter comprises a capacitor having a capacitance, and wherein the capacitance of the capacitor is used to establish the first predetermined frequency;
a low pass filter connected to the input connection in parallel with the high pass filter for receiving the input signal from the input connection, the low pass filter configured to filter the input signal and output a second filtered signal including signal frequencies less than a second predetermined frequency, the low pass filter comprises:
an operational amplifier connected in series with the input connection, the operational amplifier configured to provide a predetermined DC offset voltage to the second filtered signal;
a second output circuit connected to an output of the operational amplifier;
a feedback circuit connected between the output of the operational amplifier and an inverting input of the operational amplifier; and
a second input circuit connected to a non-inverting input of the operational amplifier, wherein at least one of the second input circuit and the second output circuit is used to establish the second predetermined frequency;

an output connection connected to the high pass filter and the low pass filter, the output connection for receiving the first filtered signal from the high pass filter and the second filtered signal from the low pass filter, the output connection configured to combine the first filtered signal and the second filtered signal to form a combined signal and provide the combined signal to a first output circuit, wherein the predetermined DC offset voltage of the second filtered signal corresponds to a DC offset voltage acceptable to the first output circuit; and
an attenuator circuit coupled to the output connection and configured to match a gain in the first filtered signal to a gain in the second filtered signal.

7. A coupling module comprising;
an input connection connected to a first input circuit to receive an input signal from the first input circuit;
a high pass filter connected to the input connection for receiving the input signal from the input connection, the high pass filter configured to filter the input signal and output a first filtered signal including signal frequencies greater than a first predetermined frequency, the high pass filter comprises a capacitor having a capacitance, and wherein the capacitance of the capacitor is used to establish the first predetermined frequency;
a low pass filter connected to the input connection in parallel with the high pass filter for receiving the input signal from the input connection, the low pass filter configured to filter the input signal and output a second filtered signal including signal frequencies less than a second predetermined frequency, the low pass filter comprises:
an operational amplifier connected in series with the input connection, the operational amplifier configured to provide a predetermined DC offset voltage to the second filtered signal;
a second output circuit connected to an output of the operational amplifier;
a feedback circuit connected between the output of the operational amplifier and an inverting input of the operational amplifier; and
a second input circuit connected to a non-inverting input of the operational amplifier, wherein at least one of the second input circuit and the second output circuit is used to establish the second predetermined frequency;

an output connection connected to the high pass filter and the low pass filter, the output connection for receiving the first filtered signal from the high pass filter and the second filtered signal from the low pass filter, the output connection configured to combine the first filtered signal and the second filtered signal to form a combined signal and provide the combined signal to a first output circuit, wherein the predetermined DC offset voltage of the second filtered signal corresponds to a DC offset voltage acceptable to the first output circuit; and
a differential circuit configured to provide an input signal to the second input circuit connected to the non-inverting input of the operational amplifier, wherein the input signal provided to the operational amplifier supports signal maintenance during long periods of unchanging signal at the input connection.

8. The coupling module of claim 7 , wherein the differential circuit is configured to generate the input signal based on information from the first output circuit.

9. The coupling module of claim 8 , wherein the dif

Assignees

• Joffe Daniel M
• Venters W Stuart
• Brethour Vern
• Adtran Inc

Inventors

• Joffe Daniel M
• Venters W Stuart
• Brethour Vern

Classifications

• G05F1/461 Primary

  using an operational amplifier as final control device · CPC title

• H03H11/126

  using a single operational amplifier (H03H11/1204 takes precedence; parallel-T filters H03H11/1295) · CPC title

• H03H11/0472

  Current or voltage controlled filters · CPC title

• H04B3/548

  the power on the line being DC (arrangements for feeding power H04L12/10; extracting feeding power from signals H04L25/02) · CPC title

• G05F5/00

  Systems for regulating electric variables by detecting deviations in the electric input to the system and thereby controlling a device within the system to obtain a regulated output · CPC title