CN107294694B

CN107294694B - Configurable bi-directional transceiver for full duplex serial link communication system

Info

Publication number: CN107294694B
Application number: CN201710226868.7A
Authority: CN
Inventors: C·伊尔马泽尔; A·K·巴佛拉; U·伊尔马泽尔
Original assignee: Maxim Integrated Products Inc
Current assignee: Maxim Integrated Products Inc
Priority date: 2016-04-06
Filing date: 2017-04-06
Publication date: 2022-05-24
Anticipated expiration: 2037-04-06
Also published as: CN107294694A; DE102017107416A1

Abstract

The configurable transceiver includes a first transmitter, an edge rate controller, a second transmitter, a subtractor, a bandwidth controller, and a main controller. The first transmitter is configured to generate a first signal for transmission via a transmission link. The second transmitter is configured to generate a replica signal associated with the first signal. The edge rate controller is communicatively coupled to the first transmitter and/or the second transmitter and configured to control an edge rate parameter of the first signal and/or the second signal. The subtractor is configured to subtract the replica signal from a signal received via the transmission link. The bandwidth controller is configured to control a bandwidth parameter of a difference signal received from an output of the subtractor. The master controller selects an edge rate and a bandwidth control word for each desired link rate. It may also automatically find the maximum possible link speed.

Description

Configurable bi-directional transceiver for full duplex serial link communication system

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No.62/318,878 entitled "configuration component guide FOR FULL-dual SERIAL LINK COMMUNICATION SYSTEM," filed 2016, 4, 6.4.f. § 119(e), which is hereby incorporated herein by reference in its entirety.

Technical Field

The invention relates to a configurable bi-directional transceiver for a full-duplex serial link communication system.

Background

Transceivers are used in various communication systems to transmit and receive signals. For example, transceivers are commonly used in communication systems including, but not limited to, telecommunication systems, vehicle (e.g., automobiles, airplanes, ships, etc.) communication systems, security systems, sound systems, television broadcast systems, internet broadcast systems, sensor systems, control systems, power distribution networks, and the like. Transceivers that can operate at different data rates are needed, for example, for data rate compatibility or to compensate for link quality degradation due to fading, reflection loss, transmission link aging, and the like.

Disclosure of Invention

According to an aspect of the present disclosure, there is provided a configurable transceiver comprising: a first transmitter configured to generate a first signal for transmission via a transmission link; an edge rate controller communicatively coupled to the first transmitter, the edge rate controller configured to control an edge rate parameter of the first signal; a second transmitter configured to generate a replica signal associated with the first signal; a subtractor communicatively coupled to the transmission link and communicatively coupled to an output of the second transmitter, the subtractor configured to subtract the replica signal from a signal received via the transmission link; and a bandwidth controller communicatively coupled to an output of the subtractor, the bandwidth controller configured to control a bandwidth parameter of a difference signal received from the output of the subtractor.

According to another aspect of the present disclosure, there is provided a communication system including: equipment; a transmission link; and a transceiver configured to communicate with the device via the transmission link, the transceiver comprising: a first transmitter configured to generate a first signal for transmission via the transmission link; an edge rate controller communicatively coupled to the first transmitter, the edge rate controller configured to control an edge rate parameter of the first signal; a second transmitter configured to generate a replica signal associated with the first signal; a subtractor communicatively coupled to the transmission link and to an output of the second transmitter, the subtractor configured to subtract the replica signal from a signal received via the transmission link; and a bandwidth controller communicatively coupled to an output of the subtractor, the bandwidth controller configured to control a bandwidth parameter of a difference signal received from the output of the subtractor.

According to another aspect of the present disclosure, there is provided a method for communication, including: generating a first signal for transmission via a transmission link; controlling an edge rate parameter of the first signal; generating a replica signal associated with the first signal; subtracting the replica signal from a signal received via the transmission link to generate a difference signal; and controlling a bandwidth parameter of the difference signal.

Drawings

The detailed description describes embodiments with reference to the drawings. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items. Various embodiments or examples of the disclosure are disclosed in the following detailed description and the accompanying drawings. The figures are not necessarily drawn to scale. In general, the operations of the disclosed processes may be performed in any order, unless otherwise specified in the claims.

Fig. 1 is a block diagram illustrating a communication system including a configurable bi-directional transceiver according to an example embodiment of the present disclosure.

Fig. 2 is a block diagram illustrating a controller for a configurable bi-directional transceiver (e.g., the configurable bi-directional transceiver of fig. 1) according to an example embodiment of the present disclosure.

Fig. 3 is a block diagram illustrating a communication system including two configurable bi-directional transceivers (e.g., the configurable bi-directional transceiver of fig. 1) according to an example embodiment of the present disclosure.

Fig. 4 is a circuit diagram illustrating circuitry of a transmitter circuit for a configurable bi-directional transceiver (e.g., the configurable bi-directional transceiver of fig. 1) according to an example embodiment of the present disclosure.

Fig. 5 is a circuit diagram illustrating circuitry of a subtractor circuit for a configurable bi-directional transceiver (e.g., the configurable bi-directional transceiver of fig. 1) according to an example embodiment of the present disclosure.

Fig. 6 is a block diagram illustrating a communication system including a configurable bi-directional transceiver according to an example embodiment of the present disclosure.

Fig. 7A is a flow chart illustrating a process for controlling an edge rate parameter and a bandwidth parameter of a configurable bi-directional transceiver (e.g., the configurable bi-directional transceiver of fig. 1 or 6) according to an example embodiment of the present disclosure.

Fig. 7B is a flow chart illustrating a process for controlling an edge rate parameter and a bandwidth parameter of a configurable bi-directional transceiver (e.g., the configurable bi-directional transceiver of fig. 1 or 6) according to an example embodiment of the present disclosure.

Fig. 7C is a flow chart illustrating a process for controlling an edge rate parameter and a bandwidth parameter of a configurable bi-directional transceiver (e.g., the configurable bi-directional transceiver of fig. 1 or 6) according to an example embodiment of the present disclosure.

Detailed Description

SUMMARY

A transceiver is a device that includes a transmitter and a receiver with shared circuitry and/or shared device structures (e.g., disposed on the same substrate and/or within a shared housing/casing). Transceivers are used in various communication systems to transmit and receive signals. For example, transceivers are commonly used in communication systems including, but not limited to, telecommunication systems, vehicle (e.g., automobiles, airplanes, ships, etc.) communication or control systems, security systems, sound systems, television broadcast systems, internet radio systems, sensor systems, control systems, power distribution networks, and the like.

The transceiver may be configured to transmit and receive signals over a transmission link. Examples of transmission links include, but are not limited to, air (e.g., for wireless transceivers, such as, but not limited to, Radio Frequency (RF) transceivers, optical transceivers, etc.), single-wire cables, multi-wire cables, coaxial cables, twisted-pair wires, fiber optics, and the like. Many factors, such as, but not limited to, attenuation, reflection loss, or transmission link aging, can affect link performance. Transceivers operable at different data rates (e.g., different transmit data rates and/or receive data rates) may be tuned to improve link performance. In some applications, it is desirable or necessary to establish a communication link between two transceivers simultaneously in both directions. However, increasing the number of physical links may be undesirable or impossible due to cost or space requirements. In this case, a simultaneous full duplex link may be implemented using a bi-directional transceiver.

A configurable transceiver having adjustable transmit and receive data rates is disclosed. The configurable transceiver includes a first (primary) transmitter, an edge rate controller, a second (replica) transmitter, a subtractor, and a bandwidth controller. The primary transmitter is configured to generate a first signal for transmission via the transmission link. An edge rate controller is communicatively coupled to the primary transmitter and configured to control an edge rate parameter of the first signal. The replica transmitter is configured to generate a replica signal associated with the first signal. A subtractor is communicatively coupled to the transmission link and the output of the replica transmitter. The subtractor is configured to subtract the replica signal from a signal received via the transmission link. In this way, the subtractor implements the receiver function of the transceiver. That is, the subtractor performs echo cancellation by subtracting the replica signal (an approximate version of the first signal) from the signal received via the transmission link. The subtractor outputs a difference signal that includes an isolated or nearly isolated data signal received via the transmission link (e.g., from another device in communication with the transceiver). A bandwidth controller is communicatively coupled to the output of the subtractor and is configured to control a bandwidth parameter of a difference signal received from the output of the subtractor. In some embodiments, the configurable transceiver may be configured to monitor at least one signal parameter (e.g. peak-to-peak amplitude) of the difference signal output by the subtractor and to control an edge rate and/or bandwidth parameter of the transmitted and received signals based on the signal parameter.

Exemplary embodiments

Fig. 1 illustrates a communication system 100 in accordance with an embodiment of the present disclosure. Examples of communication system 100 may include, but are not limited to, telecommunication systems, vehicle (e.g., automobile, aircraft, marine, etc.) communication or control systems, security systems, sound systems, television broadcast systems, internet broadcast systems, sensor systems, control systems, power distribution networks, and the like. The communication system 100 includes a configurable transceiver 101 and a device 118 communicatively coupled to each other by a transmission link 112 (e.g., air, single wire cable, multi-wire cable, coaxial cable, twisted pair, fiber, etc.). Device 118 may include any electronic device configured to transmit signals and/or receive signals. For example, the devices 118 may include, but are not limited to, transceivers, transmitters, receivers, repeaters, and the like.

The transceiver 101 and the device 118 may be configured to communicate data signals bi-directionally. For example, the transceiver 101 may be configured to transmit data signals to the device 118 and receive data signals from the device 118. In such embodiments, transmission link 112 can convey forward channel data (e.g., a data signal transmitted by transceiver 101 to device 118) and reverse channel data (e.g., a data signal transmitted by device 118 to transceiver 101) simultaneously or substantially simultaneously. To isolate the backchannel data, the transceiver 101 may be configured to subtract the forward channel data or an approximate form of the forward channel data (e.g., a replica version, a near-replica version, or a scaled version) from the total channel data received via the transmission link 112. As discussed further herein, transceiver 101 may include subtractor 106, subtractor 106 implementing the receiver function of transceiver 101 by subtracting forward channel data or an approximate form of forward channel data from total channel data received via transmission link 112 to isolate reverse channel data.

As shown in fig. 1, the transceiver 101 includes a primary transmitter 102 and a replica transmitter 104. The main transmitter 102 is configured to generate a first signal for transmission via the transmission link 112. For example, the main transmitter 102 has an output 108 communicatively coupled to the transmission link 112. Replica transmitter 104 is configured to generate a replica signal associated with the first signal. In some embodiments, both the primary transmitter 102 and the replica transmitter 104 may receive at least one input from the pre-driver 103, the pre-driver 103 controlling transmission characteristics/parameters of the primary transmitter 102 and the replica transmitter 104. The replica transmitter 104 may be configured to generate a replica signal comprising the same version, nearly the same version, or a scaled and/or shifted version of the first signal.

The transceiver 101 includes an edge rate controller 122 communicatively coupled to the main transmitter 102. The edge rate controller 122 is configured to control an edge rate parameter (e.g., edge rate, slew rate, etc.) of the first signal. For example, the edge rate controller 122 may control the edge rate parameter of the first signal by tuning the input parameter of the primary transmitter 102. In an embodiment, the edge rate controller 122 (or a second edge rate controller) is communicatively coupled to the replica transmitter 104 and configured to control an edge rate parameter of the replica signal (e.g., in a similar manner as the edge rate parameter of the first signal). The edge rate controller 122 may include a tunable component 123 (e.g., a tunable capacitor, a tunable resistor, or another tunable electronic component). The edge rate controller 122 may be controlled by a computer (e.g., by the controller 126 shown in fig. 2) and/or driven by one or more outputs of the transceiver 101 (e.g., driven in accordance with a signal parameter measured at the output 108, the output 110, or the output 114).

The transceiver 101 also includes a subtractor 106 communicatively coupled to the transmission link 112 and to an output 110 of the replica transmitter 104. The subtractor 106 is configured to subtract a replica signal (e.g., a data signal comprising forward channel data or an approximate form of the forward channel data) from a signal (e.g., a data signal comprising total channel data) received via the transmission link 112. In this way, the subtractor 106 implements the receiver function of the transceiver 101. For example, the subtractor 106 can be configured to perform echo cancellation by subtracting a replica signal (e.g., an echo or reflected approximate version of the first signal) from the signal received via the transmission link 112. The subtractor 106 outputs a difference signal that includes an isolated or nearly isolated data signal received via the transmission link 112 (e.g., the subtractor 106 outputs a data signal that includes backchannel data received from the device 118). In some embodiments, subtractor 106 comprises a programmable gain amplifier and one or more suitable equalizer circuits (e.g., a continuous-time linear equalizer (CTLE), a decision feedback equalizer [ DFE ], etc.).

The subtractor 106 has a bandwidth controller 124 communicatively coupled to the output 114 of the subtractor 106. The bandwidth controller 124 is configured to control a bandwidth parameter (e.g., signal bandwidth) of the difference signal received from the output 114 of the subtractor 106. For example, the bandwidth controller 124 may include a tunable component 125 (e.g., a tunable capacitor, a tunable resistor, or another tunable electronic component) coupled to the output 114 of the controller 124. The bandwidth controller 124 may be controlled by a computer (e.g., by the controller 126 shown in fig. 2) and/or driven by one or more outputs of the transceiver 101 (e.g., driven in accordance with signal parameters measured at the output 114).

The transceiver 101 (including some or all of its components) may operate under computer control. For example, fig. 2 shows a controller 126, the controller 126 configured to interface with the edge rate controller 122, the bandwidth controller 124, the peak detector 116, the pre-driver 103, the primary transmitter 102, the replica transmitter 104, the subtractor 106, and/or other components of the transceiver 101. In some embodiments, transceiver 101 includes controller 100. In other embodiments, the controller 126 may be communicatively coupled to the transceiver 101. Processor 128 may be included with controller 126 or within controller 126 to control the components and functions of transceiver 101 and/or communication system 100 described herein using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or a combination thereof. The terms "controller," "functionality," "service," and "logic" as used herein generally represent software, firmware, hardware, or a combination of software, firmware, or hardware in conjunction with controlling the transceiver 101. In the case of a software implementation, the module, functionality, or logic represents program code (e.g., an algorithm embodied in a non-transitory computer-readable medium) that performs specified tasks when executed on a processor (e.g., a Central Processing Unit (CPU) or CPUs). The program code can be stored in one or more non-transitory computer-readable memory devices or media (e.g., internal memory and/or one or more tangible media), etc. For example, memory may include, but is not limited to, volatile memory, non-volatile memory, flash memory, SRAM, DRAM, RAM, and ROM. The structures, functions, methods, and techniques described herein may be implemented on a variety of commercial computing platforms having a variety of processors.

Controller 126 may include a processor 128, memory 130, and a communication interface 132. The processor 128 provides at least the processing functions for the controller 126, and the processor 128 may include any number of processors, microcontrollers, circuits, Field Programmable Gate Arrays (FPGAs), or other processing systems, as well as resident memory or external memory for storing data, executable code, and other information accessed or generated by the controller 126. Processor 128 may execute one or more software programs embodied in a non-transitory computer readable medium that implements the techniques described herein. Processor 128 is not limited by the materials from which it is formed or the processing mechanisms employed therein, and as such may be implemented via semiconductor(s) and/or transistor(s) (e.g., using electronic Integrated Circuit (IC) components), etc.

The controller 126 may include memory 130 (e.g., flash, RAM, SRAM, DRAM, ROM, etc.). The memory 130 may be an example of a tangible computer-readable storage medium that provides storage functionality to store various data and/or program code (e.g., software programs and/or code segments) associated with operation of the controller 126, or other data for directing the processor 128 (and possibly other components of the transceiver 101/controller 126 as well) to perform the functions described herein. Thus, the memory 130 may store data such as programs of instructions for operating the transceiver 101 (including components thereof). It should be noted that while a single memory 130 is described, multiple types and combinations of memories (e.g., tangible, non-transitory memories) may be employed. The memory 130 may be integrated with the processor 128, may comprise a separate memory, or may be a combination of both.

Some examples of memory 130 may include removable and non-removable memory components such as Random Access Memory (RAM), Read Only Memory (ROM), flash memory (e.g., Secure Digital (SD) memory cards, mini SD memory cards, and/or micro SD memory cards), magnetic memory, optical memory, Universal Serial Bus (USB) memory devices, hard disk memory, external memory, and so forth. In an embodiment, transceiver 101 and/or memory 130 may include removable Integrated Circuit Card (ICC) memory, e.g., memory provided by a Subscriber Identity Module (SIM) card, Universal Subscriber Identity Module (USIM) card, Universal Integrated Circuit Card (UICC), or the like.

Controller 126 may include a communication interface 132. The communication interface 132 may be operably configured to communicate with components of the transceiver 101. For example, the communication interface 132 may be configured to transmit data stored in the transceiver 101, retrieve data from storage in the transceiver 101, and so forth. The communication interface 132 may also be communicatively coupled with the processor 128 to facilitate data transfer between components of the transceiver 101 and the processor 128 (e.g., to communicate inputs received from devices communicatively coupled with the transceiver 101/controller 126 to the processor 128). It should be noted that although communication interface 132 is described as a component of controller 126, one or more components of communication interface 132 may be implemented as external components communicatively coupled to transceiver 101 via a wired connection and/or a wireless connection. The transceiver 101 may also include and/or be connected to one or more input/output (I/O) devices (e.g., via the communication interface 132), such as a display, a mouse, a touchpad, a touchscreen, a keyboard, a microphone (e.g., for voice commands), and so forth.

The communication interface 132 and/or the processor 128 may be configured to communicate with various networks, for example, a wide area cellular telephone network such as a cellular network, a 3G cellular network, a 4G cellular network, or a global system for mobile communications (GSM) network; a wireless computer communication network such as a WiFi network (e.g., a Wireless Local Area Network (WLAN) operating using the IEEE802.11 network standard); ad hoc wireless networks, the internet; the internet; a Wide Area Network (WAN); a Local Area Network (LAN); a Personal Area Network (PAN) (e.g., a Wireless Personal Area Network (WPAN) operating using the IEEE 802.15 network standard); a public telephone network; an extranet; an intranet, etc. However, this list is provided as an example only and is not intended to limit the present disclosure. Further, the communication interface 132 may be configured to communicate with a single network or multiple networks through different access points. In particular embodiments, communication interface 132 may transmit information from controller 126 to an external device (e.g., a cellular phone, a computer connected to a WiFi network, cloud storage, etc.). In another particular embodiment, the communication interface 132 may receive information from an external device (e.g., a cellular phone, a computer connected to a WiFi network, cloud storage, etc.).

Generally, any of the functions described herein can be implemented using hardware (e.g., fixed logic circuitry such as an integrated circuit), software, firmware, manual processing, or a combination thereof. Thus, the blocks discussed in the above disclosure generally represent hardware (e.g., fixed logic circuitry such as an integrated circuit), software, firmware, or a combination thereof. In the example of a hardware configuration, the various blocks discussed in the above disclosure may be implemented as an integrated circuit along with other functionality. Such an integrated circuit may include all of the functionality of a given block, system, or circuit, or a portion of the functionality of a block, system, or circuit. Furthermore, elements of a block, system, or circuit may be implemented across multiple integrated circuits. Such integrated circuits may include a variety of integrated circuits, including but not necessarily limited to: monolithic integrated circuits, flip-chip integrated circuits, multi-chip module integrated circuits, and/or mixed signal integrated circuits. In a software-implemented example, the various blocks discussed in the above disclosure represent executable instructions (e.g., program code) that perform specified tasks when executed on a processor. The executable instructions may be stored in one or more tangible computer-readable media. In some such instances, the entire system, block, or circuit may be implemented using its software or firmware equivalents. In other examples, one portion of a given system, block, or circuit may be implemented as software or firmware, while other portions may be implemented as hardware.

Referring again to fig. 1, the transceiver 101 may be configured to monitor at least one signal parameter (e.g., peak-to-peak amplitude) of the difference signal output by the subtractor 106, and to control an edge rate and/or bandwidth parameter of the transmitted and received signals based on the signal parameter. In an embodiment, subtractor 106 is communicatively coupled to peak detector 116. The peak detector 116 is configured to measure at least one signal parameter (e.g., peak-to-peak (p-p) amplitude) of the difference signal. The peak detector 116 may be configured to generate a parameter signal (e.g., a peak signal) representative of the measured signal parameter (e.g., p-p amplitude). The parameter signal (or measured signal parameter) may be used to tune (e.g., adjust, modify, control, etc.) one or more parameters of the primary transmitter 102 and/or the replica transmitter 104. For example, the tuned parameters may include amplitude, edge rate, bandwidth, peak, delay, combinations thereof, and the like.

In an embodiment, the main transmitter 102 is an edge rate programmable transmitter and the subtractor 106 functions as a bandwidth programmable receiver. The main transmitter 102 and the subtractor 106 are programmed according to data rates in two directions, e.g., a forward channel (transmit) direction and a reverse channel (receive) direction. Reducing the edge rate parameter of the first signal generated at the primary transmitter 102 may reduce reflections and high frequency ringing; however, doing so may limit the data rate. Similarly, reducing the bandwidth of the difference signal may filter the high frequency components; however, doing so may also affect the data rate. The edge rate controller 122 and the bandwidth controller 124 may be controlled or automatically adjusted (e.g., self-adjusting) to maintain link performance without unduly reducing the data rate of the forward and reverse channels of the communication system 100. In an embodiment, the edge rate controller 122 is configured to control the edge rate parameter of the first signal and/or the replica signal based on the signal parameter measured by the peak detector 116. The bandwidth controller 124 may also be configured to control the bandwidth of the difference signal output by the subtractor 106 based on the signal parameters measured by the peak detector 116 and/or based on the edge rate or data rate of the transceiver 101.

Fig. 3 illustrates an embodiment of a communication system 100 configured as a full duplex communication system. For example, device 118 may include a second transceiver constructed similarly to transceiver 101. In this embodiment, the device 118 may include a primary transmitter 142, a replica transmitter 144, a subtractor 146, and possibly other components, such as those in the same or similar structural arrangement in the transceiver 101. If the data rate of the transmitter 102 in the first direction D1 remains constant (or at a maximum), the data rate in the other direction D2 depends on the link quality (e.g., attenuation, reflection loss, etc.). The edge rate of the transmitter 142 and the bandwidth of the subtractor 106 may be programmed based on the link quality (e.g., based on the eye opening or Bit Error Rate (BER) determined by the controller 126). If the link is desired to be symmetric, the edge rate parameters of the transmitter 102 and the transmitter 142 and the bandwidth parameters of the subtractor 106 and the subtractor 146 may be similarly programmed (e.g., set to the same or nearly the same edge rate and bandwidth).

In some embodiments, the controller 126 is configured to tune the edge rate controller 122 and/or the bandwidth controller 124 based on at least one signal parameter measured by the peak detector 116. For example, the controller 126 may be configured to reduce the edge rate of the transmitter 102 via the edge rate controller 122 until the target p-p amplitude is reached at the output 114 of the subtractor 116. In an embodiment, the controller 126 is configured to access a lookup table 134 in the memory 130 to determine a data rate corresponding to the edge rate. The controller 126 is then configured to adjust 146 the bandwidth parameter via the bandwidth controller 124 based on the data rate determined by the controller 126. Alternatively, the receiver of 118 may detect the incoming data rate and adjust its bandwidth accordingly.

In some embodiments, subtractor 106 is configured to modify its gain and equalizer coefficients when a signal from transmitter 142 is transmitted (e.g., in direction D2) and channel data in direction D1 is idle. After the modification phase is completed, the subtractor may set its parameters (e.g., gain, etc.) such that a predefined swing is obtained at its output. The same gain and equalizer settings may be used when measuring the residual noise (or echo) caused by the transmitter 102. The transceiver 101 and the device 118 (e.g., the second transceiver) may be configured to implement a handshake protocol to enable and disable the D1 or D2 channels during calibration.

Once the transmitter edge rate and receiver bandwidth are determined, the transceiver 101 may be configured to match the output of the replica transmitter 104 to the output of the transmitter 102. The transmitter 102 can achieve both low output capacitance and wide range edge rate control. In an embodiment, the edge rate controller 122 is configured to achieve low output capacitance by programming the edge rate of the pre-driver 103 driving the main transmitter 102 or the replica transmitter 104.

In an embodiment, the controller 126 is configured to monitor the final driver stage and decrease the pre-driver amplitude until the output of the transmitter 102 begins to decrease. In this way, the final stage is not saturated and the edge rate can be controlled at the input of the driver rather than at its output. For example, the peak detector 116 may be configured to monitor the output of the transmitter 102 while keeping the replica transmitter 104 in a powered down state. The controller 126 may be configured to monitor the final driver stage based on the signal parameter (e.g., p-p amplitude) measured by the peak detector 116, and may reduce the pre-driver amplitude until the signal parameter satisfies the threshold signal parameter. In an embodiment, the feedback procedure is applied at start up, although there is no transmission from the other side. In the feed-forward approach, the controller 126 may be configured to detect a DC value of the predriver input amplitude that does not saturate the final stage, which may cause a few percent of the tail current to flow into the off transistors of the switch pair.

In another embodiment, the controller 126 may be configured to determine the amplitude of the predriver 103 based on a stored value in the look-up table 134 that corresponds to the selected transmitter 102 output amplitude. This method can be applied if the saturation voltage crosses the process corner in the selected process without changing. However, the saturation voltage may vary with temperature. Bias current I_PRECan be covered withConfigured to track the saturation voltage of the final drive across temperature.

Referring to fig. 4, the controller 126 may be configured to be based on the current I through the main transmitter 102_CMLTo set the bias current I of the pre-driver 103_PRE. Bias current I of predriver 103_PREIs I_CMLA scaled version of (a). Similarly, the resistive element Rrep of the replica transmitter 104 is a scaled version of the resistive element R1. In an embodiment, the resistive element R1 is a fifty ohm (50 ohm) resistor. However, it should be understood that the resistive element R1 may have other resistance values depending on the design and configuration of the transceiver 101. In an embodiment, resistive elements R1 and Rrep are calibrated. However, it should be understood that depending on the process technology, calibration may not be mandatory.

In the embodiment shown in fig. 4, the edge rate controller 122 signals the capacitance at the output of the pre-driver 103, thereby controlling the edge rate parameters of the pre-driver 103 and thus the main transmitter 102 and/or replica transmitter 104. For example, the edge rate controller 122 may include at least one tunable capacitor. Tunable capacitors may be formed with different types of capacitors (e.g., metal-insulator-metal capacitors, MOS device capacitances, etc.).

Fig. 5 shows an embodiment of the subtractor 106 and the bandwidth controller 124. The subtractor 106 subtracts the replica signal from the first signal and filters out high frequency components. For example, as shown in fig. 5, the subtractor 106 may have a Direct Current (DC) blocking circuit 105 at an input of the subtractor 106 between the

transmitters

102 and 104 and the subtractor 106 to filter out high frequency components (e.g., DC signal components) in the first signal and the replica signal. As shown in FIG. 5, the inputs OTX +, OTX-, OREP +, and OREP-may be arranged to support differential and single-ended communication links. In differential operation, current sources ISUB1 and ISUB2 are both turned on. In single-ended operation, one of current sources ISUB1 or ISUB2 is turned on, depending on which single-ended output of subtractor 106 is being used.

In another embodiment, the transceiver 101 may employ termination elements of the replica transmitter 104 to better match the main transmitter 102 load to the replica transmitter 104 load. In an embodiment, the output of the main transmitter 102 is loaded by a package inductance in a series characteristic impedance (e.g., a fifty ohm (50 ohm) link impedance, etc.). In some embodiments, as shown in fig. 6, an inductor L in series with the lower resistive element Rrep 2 is coupled to the upper resistive element Rrep 1 to mitigate package inductance effects that may result in lower residual noise. The inductor L may be tuned by various suitable methods to control the peak of the replica transmitter 104. The transceiver 101 may also include a capacitor Cac in series with the inductor L to block the DC portion of the replica signal. However, in some embodiments, capacitor Cac may not be employed, for example, when inductor L is connected to a supply voltage rather than ground.

In some embodiments, the controller 126 may be configured to execute a lock algorithm and an eye opening algorithm to determine whether to decrease or increase the data rate during calibration at power up. For example, the controller 126 may be configured to set the edge rate and bandwidth parameters to the highest rate in both the forward and reverse channel directions. The controller 126 may be configured to reduce the reverse channel speed (and adjust the configuration of the transceiver 101 accordingly) until both sides lock with acceptable eye opening without error. In another embodiment, the controller 126 may set the edge rate and bandwidth parameters to achieve the highest data rate in the forward channel direction and the lowest data rate in the reverse channel direction. The controller 126 can then be configured to increase the reverse channel to a maximum setting at which the transmission link 112 still performs within an acceptable margin of error (e.g., below a threshold BER).

Exemplary procedure

Fig. 7A-7C illustrate an exemplary embodiment of a process 300 for controlling edge rate and bandwidth parameters of a configurable transceiver (e.g., configurable transceiver 101 of communication system 100 shown in fig. 1-6) using the techniques described herein. In general, the operations of procedure 300 may be performed in any order, unless otherwise provided in the claims.

As shown in fig. 7A, the process 300 includes generating a first signal for transmission via the transmission link 112 (block 302). For example, the main transmitter 102 of the transceiver 101 may generate a first signal for transmission via the transmission link 112. An edge rate parameter of the first signal 304 is controlled to affect a forward channel (e.g., transmit) data rate (block 304). For example, the edge rate controller 124 of the transceiver 101 may control the edge rate parameter of the first signal by tuning the input parameter of the main transmitter 102.

A replica signal associated with the first signal is generated (block 306). For example, replica transmitter 104 of transceiver 101 can generate a replica signal. In an embodiment, the replica signal comprises the same version, almost the same version, a scaled and/or shifted version of the first signal. The edge rate controller 122 may also control an edge rate parameter of the replica signal (e.g., in a similar manner as the edge rate parameter of the first signal).

The replica signal can be subtracted from the signal received via the transmission link 112 to generate a difference signal (block 308). For example, the subtractor 106 of the transceiver 101 can subtract a replica signal (e.g., a data signal comprising forward channel data or an approximate form of the forward channel data, D1 in fig. 3) from a signal (e.g., a data signal comprising total channel data) received via the transmission link 112. The subtractor 106 outputs a difference signal that includes the isolated or nearly isolated data signal received via the transmission link 112 (e.g., the subtractor 106 outputs a data signal that includes the backchannel data received from the device 118, D2 in fig. 3). The bandwidth parameter of the difference signal is controlled to affect the reverse channel (e.g., received) data rate (block 310). For example, the bandwidth controller 124 of the transceiver 101 may control the bandwidth parameter of the difference signal received from the output 114 of the subtractor 106.

In some embodiments, the edge rate parameter and/or the bandwidth parameter is controlled based on one or more signal parameters of the difference signal. For example, as shown in fig. 7B, the process 300 may further include measuring at least one signal parameter of the difference signal (312). In an embodiment, the peak detector 116 of the transceiver may measure a signal parameter (e.g., p-p amplitude) of the difference signal at the output 114 of the subtractor. An edge rate parameter of the first signal may be controlled based on the measured signal parameter (block 314). For example, the edge rate controller 122 may control (or be adjusted to control) the edge rate parameter of the first signal based on the measured signal parameter. In some implementations, the edge rate parameter of the first signal is adjusted (e.g., decreased) until the signal parameter of the difference signal satisfies a threshold signal parameter (e.g., a threshold p-p amplitude) (block 316). The bandwidth parameter may be controlled based on the adjusted edge rate parameter. For example, as shown in fig. 7C, the process 300 may include determining a data rate associated with the edge rate parameter based on a lookup table (block 318). In an embodiment, the controller 126 may access a lookup table to determine a data rate corresponding to the adjusted edge rate parameter of the first signal. A bandwidth parameter of the difference signal may be controlled based on the determined data rate (block 320). For example, the bandwidth controller 124 may control (or may be adjusted to control) the bandwidth of the difference signal.

Conclusion

Although the subject matter has been described in language specific to structural features and/or procedural operations, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A configurable transceiver, comprising:

a first transmitter configured to generate a first signal for transmission via a transmission link;

an edge rate controller communicatively coupled to the first transmitter, the edge rate controller configured to: controlling an edge rate parameter of the first signal based on a signal parameter measured by a peak detector;

a second transmitter configured to generate a replica signal associated with the first signal;

a subtractor communicatively coupled to the transmission link and communicatively coupled to an output of the second transmitter, the subtractor configured to subtract the replica signal from a signal received via the transmission link; and

a bandwidth controller communicatively coupled to an output of the subtractor, the bandwidth controller configured to: controlling a bandwidth parameter of a difference signal received from the output of the subtractor based on a signal parameter measured by the peak detector and/or based on an edge rate or data rate of the configurable transceiver.

2. The configurable transceiver of claim 1, wherein the edge rate controller is further communicatively coupled to the second transmitter and configured to control an edge rate parameter of the replica signal.

3. The configurable transceiver of claim 1, further comprising the peak detector communicatively coupled to an output of the subtractor, the peak detector configured to measure at least one signal parameter of the difference signal.

4. The configurable transceiver of claim 3, wherein the second transmitter is tuned based on the at least one signal parameter of the difference signal.

5. The configurable transceiver of claim 3, wherein the edge rate controller is configured to control the edge rate parameter of the first signal based on the at least one signal parameter of the difference signal.

6. The configurable transceiver of claim 5, wherein the edge rate controller is configured to adjust the edge rate parameter of the first signal until the at least one signal parameter of the difference signal satisfies a threshold signal parameter.

7. The configurable transceiver of claim 6, further comprising a controller comprising a processor and a memory, the processor configured to determine a data rate associated with the edge rate parameter based on a lookup table stored by the memory, wherein the bandwidth controller is configured to control the bandwidth parameter of the difference signal based on the data rate determined by the processor.

8. The configurable transceiver of claim 1, wherein the edge rate controller comprises at least one of a tunable capacitor or a tunable resistor.

9. The configurable transceiver of claim 1, wherein the bandwidth controller comprises at least one of a tunable capacitor or a tunable resistor.

10. A communication system, comprising:

equipment;

a transmission link; and

a transceiver configured to communicate with the device via the transmission link, the transceiver comprising:

a first transmitter configured to generate a first signal for transmission via the transmission link;

a bandwidth controller communicatively coupled to an output of the subtractor, the bandwidth controller configured to: controlling a bandwidth parameter of a difference signal received from the output of the subtractor based on a signal parameter measured by the peak detector and/or based on an edge rate or data rate of the transceiver.

11. The communication system of claim 10, wherein the edge rate controller is further communicatively coupled to the second transmitter and configured to control an edge rate parameter of the replica signal.

12. The communication system of claim 10, further comprising the peak detector communicatively coupled to an output of the subtractor, the peak detector configured to measure at least one signal parameter of the difference signal.

13. The communication system of claim 12, wherein the second transmitter is tuned based on the at least one signal parameter of the difference signal.

14. The communication system of claim 13, wherein the edge rate controller is configured to control the edge rate parameter of the first signal based on the at least one signal parameter of the difference signal.

15. The communication system of claim 14, wherein the edge rate controller is configured to adjust the edge rate parameter of the first signal until the at least one signal parameter of the difference signal satisfies a threshold signal parameter.

16. The communication system of claim 15, further comprising a controller comprising a processor and a memory, the processor configured to determine a data rate associated with the edge rate parameter based on a lookup table stored by the memory, wherein the bandwidth controller is configured to control the bandwidth parameter of the difference signal based on the data rate determined by the processor.

17. A method for communication, comprising:

generating a first signal for transmission via a transmission link;

controlling an edge rate parameter of the first signal based on a measured signal parameter associated with peak detection;

generating a replica signal associated with the first signal;

subtracting the replica signal from a signal received via the transmission link to generate a difference signal; and

controlling a bandwidth parameter of the difference signal based on the measured signal parameter and/or based on an edge rate or a data rate.

18. The method of claim 17, wherein controlling the edge rate parameter of the first signal comprises:

measuring at least one signal parameter of the difference signal;

controlling the edge rate parameter of the first signal based on the at least one signal parameter of the difference signal.

19. The method of claim 18, wherein controlling the edge rate parameter of the first signal based on the at least one signal parameter of the difference signal comprises:

adjusting the edge rate parameter of the first signal until the at least one signal parameter of the difference signal satisfies a threshold signal parameter.

20. The method of claim 19, wherein controlling the bandwidth parameter of the difference signal comprises:

determining a data rate associated with the edge rate parameter based on a lookup table; and

controlling the bandwidth parameter of the difference signal based on the data rate.