Method and apparatus for generating a pulse width modulated signal and optical attenuator controlled by a pulse width modulated signal
A pulse width modulation signal and device technology, applied in pulse duration/width modulation, optics, nonlinear optics, etc., can solve problems such as increasing the cost of digital circuits, limiting the clock frequency of digital circuits, and increasing power consumption of circuits
Inactive Publication Date: 2008-09-03
M(DGP1)有限公司 +1
View PDF1 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
The disadvantage of this circuit is that the power dissipation in the power tube is close to that of the associated thermoelectric element
The traditional way to increase the PWM resolution is to use a higher master clock frequency f clk ; This method will drastically increase the cost of the corresponding digital circuit and increase the operating power consumption of the circuit
Moreover, in practical applications, the clock frequency that digital circuits can achieve is limited.
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0042] Referring to FIG. 1 , a PWM circuit 10 is illustrated in FIG. 1 , which is used to control the current entering the Seebeck effect heating element 30 . As will be explained below, heating elements are often used to control the temperature and thus operate electro-optical components such as attenuators, filters or solid-state lasers.
[0043] The circuit 10 comprises a PWM controller 20, and four MOSFET switches SW1, SW2, SW3, SW4. Element 30 is what is known as a "Peltier element". Controller 20 includes a master clock generator 50 , a counter logic unit 60 and an interface logic unit 70 .
[0044] Next, the connection among the various components in the circuit 10 will be described, and the interconnection relationship is described in FIG. 1 .
[0045] Each of the switches SW1, SW2, SW3, SW4 comprises a first electrode, a second electrode and an associated gate G. A potential is applied to the gate G to control the flow from the first electrode E1 to the second elect...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
A method of generating a pulse width modulated (PWM) signal comprises: receiving digital demand data Vcontrol comprising at least one more significant bit (bit7 to bit14) and at least one less significant bit (bit0 to bit6). The PWM signal comprises a sequence of one or more frames (100), each frame: comprising a plurality of PWM pulses (W1 to W127) whose duty cycle is substantially governed by the at least one more significant bit (bit7 to bit14); and having at least one of its PWM pulses selected to have its duty cycle modified in response to the at least one less significant bit (bit0 to bit6); each of the at least one less significant bit (bit0 to bit6) uniquely mapping onto the at least one selected PWM pulse of the frame (100). The invention is also concerned with apparatus operable according to the above method and an optical attenuator whose optical attenuation is dependent upon its temperature and in which the temperature an hence attenuation is controlled using the above PWM signal.
Description
technical field [0001] The present invention relates to a method and apparatus for generating a pulse width modulated (PWM) signal. More specifically, the present invention relates to temperature control of electro-optical components, such as attenuators, filters, and solid-state lasers. These elements are used in optical communication systems. Also, although not exclusively, the present invention generally relates to an optical attenuator with enhanced resolution for use in an optical communication system. Background technique [0002] In traditional optical communication systems, optical attenuators are used to adjust and control the optical radiation propagation power in the system. This attenuation is necessary to avoid saturation of sensitive optical components, such as detectors and optical amplifiers, and to ensure that the optical radiation is of sufficient intensity to avoid being swamped by noise. Saturation can lead to loss of information and thus errors in the...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): H03K7/08H03M1/82G02F1/01
CPCG02F1/0121G02F1/0147G02F2203/48
Inventor R·W·布朗E·A·丹尼斯D·W·瓦斯G·布特勒M·J·利奇
Owner M(DGP1)有限公司