Patent Publication Number: US-2009227142-A1

Title: Audio connector with ganged articulation networks

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of U.S. patent application Ser. No. 11/619,848, filed Jan. 4, 2007, which claims priority to provisional application 60/756,057, filed Jan. 4, 2006. This application also claims priority to provisional application 61/003,256, filed Nov. 15, 2007. 
    
    
     BACKGROUND 
     The modern Western Chromatic scale has been around for some time. However, there was much debate initially regarding the “interval”, or space, between neighboring notes. 
     For example, Pythagoras, Philolaos, Boethius and Zarlino, who were rationalists, justified their systems based on numerical relations (2/1, 3/2, 9/8, 5/4, etc.). Zarlino justifies his system of scenario using only the first six numbers; there were only six planets known at the time. 
     More complex scenarios, such as the notion of overtones and acoustics comes later, in the XVII century, with Sauveur. Historically, other tone systems were proposed giving rise to other categories of consonances. 
     For example Archytas, a student of Philolaos, noticed that all the “Pythagorean ratios”, such as 2/1, 3/2, 4/3, and 9/8, are epimore (superparticular [n+1/n]), and built another system based on the superparticular ratios. He also built another system based on the Pythagorean scale that contained four fifths and five fourths, giving more commensurabilities than can be attained from any other eight notes. 
     Eventually, the modern chromatic scale emerged that divided the space between octaves (a doubling of a note) into twelve intervals. Each note in the chromatic scale is referred to in music theory according to its relative position in the scale, i.e., the note after the root note is the “second”, the next note is the “third” and so on. 
     In modern music, not all of the twelve available notes are used in every situation. A smaller subset of notes defining a scale is used. For example, the backbone of Western music is formed using the diatonic scale wherein music is composed in major and minor keys—a system codified more than 300 years ago. In this hierarchical scheme, out of the twelve possible tones of the chromatic scale, seven enjoy elevated status. In popular music, the pentatonic scale is prevalent, a scale that uses only five notes. 
     In particular, the characteristics of the octave and the fifth are highly significant, because these two intervals can be regarded as the origin of the chromatic tone scale. Indeed, as was basically shown by Pythagoras, the entire chromatic scale emerges “automatically” when the criterion is employed that the scale must include both the octave and the fifth interval above and below any tone that previously was determined. 
     Historically, each interval of the chromatic scale was given a role in keeping with the presence of the church at the time. For example, the first and fifth in a scale are absolute monarchs: without them, there can be no music. The third, fourth and seventh intervals are aristocrats—mighty lords of harmony. Most complex and interesting harmonies are built using these “melody notes”. The second and sixth intervals are more like clergy: influential within their proper sphere. The remaining five tones are music&#39;s canaille, the street mob. 
     Thus, certain intervals of the scale impart more impact or feeling that others. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a graphical illustration of the articulation response of a typical audio cable. 
         FIG. 2  is an assembly drawing of a networked connector in accordance with the teachings of this disclosure; 
         FIG. 3  shows a side view of a PCB assembly in accordance with the teachings of this disclosure; 
         FIG. 4  is a view of the back side of a PCB assembly in accordance with the teachings of this disclosure; 
         FIG. 5  shows an exemplary circuit in schematic form in accordance with the teachings of this disclosure; 
         FIG. 6  shows the front surface of a PCB assembly in accordance with the teachings of this disclosure; and 
       Referring now to  FIG. 7 , a cross-sectional assembly diagram of networked connector is shown assembled in accordance with the teachings of this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure provides for compensating for articulation problems in audio cable. Generally speaking, articulation refers to audible qualities that enable us to hear in 3-D. The articulation of an electrical circuit or network follows the shape of the “Q”. The inverse of the “Q” is called the dampening factor. 
     An audio cable may be modeled as a having a series inductive element formed by the conductors, and a parallel capacitive component formed by the space between the two conductors. Thus, an audio cable forms a network having its own articulation characteristics. 
       FIG. 1  is a graphical representation of the articulation response of a typical audio cable. Note that the articulation rises with frequency, peaking in a region labeled A. Region A shows that normal audio cable have a narrow articulation range defined by a single random pole that is arbitrarily created by the electrical characteristics of the cable. 
     The narrow articulation range of the region A is audible to listeners as the articulation affects audible information in the frequency range of the region. A narrow articulation peak can have the effect of unnaturally modifying the timbre and presence of music or speech. 
     An object of this disclosure is to provide a wider and flatter articulation range throughout the audio spectrum. Such a wide, flat articulation range is desired because it will not change the timbre or presence of the music or speech. 
     One method disclosed herein for providing a desirable articulation response profile is to provide a gang of networks that maintain a substantially constant Q throughout the audio spectrum. A constant Q is very desirable because the music/speech will not possess non-linear peaks in presence or non-linear shifts of the timbre. 
     In preferred embodiments, the articulation of a single-pole cable or network is normalized by placing ganged multiple networks at pre-determined intervals. Component values of the circuits are chosen such that the circuit has a desired articulation characteristic at a desired frequency. Multiple circuits may then be provided that are each designed to operate in an individual frequency slot. The articulation circuits may be spaced along the frequency axis at pre-defined intervals. In preferred embodiment, target frequency slots are chosen that correspond to notes or intervals in a musical scale. 
     The process of articulation normalization begins with choosing a starting or reference frequency. It is contemplated that the natural peak articulation frequency of a cable may be used, such as the peak illustrated in  FIG. 1 . Alternatively, a desired note may be chosen, such as the lowest note in a particular scale. 
     Once a reference frequency is determined, target frequency slots are calculated having frequency intervals corresponding to desired intervals of a desired scale. A gang of articulation networks are then provided that populate the desired intervals throughout the audio spectrum. The intervals at which the articulation networks are deployed may be chosen in a wide variety of ways. For example, the constituent members of the network gang may each be spaced at intervals of octaves or fifths throughout the audio spectrum. 
     Alternatively, the articulation network gang may be placed along a desired music scale such as the pentatonic or diatonic scales. It is contemplated that ratios other than music scales may be used as well, such as Pythagoras or Fibonacci numbers may be used to calculate articulation intervals. 
     Examples of intervals of a given scale and their respective ratios are given in the following table: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                   
                 frequency 
               
               
                   
                 Interval 
                 ratio 
               
               
                   
                   
               
             
            
               
                   
                 Unison 
                 1.000000:1 
               
               
                   
                 Semitone or minor second 
                 1.059463:1 
               
               
                   
                 Whole tone or major second 
                 1.122462:1 
               
               
                   
                 Minor third 
                 1.189207:1 
               
               
                   
                 Major third 
                 1.259921:1 
               
               
                   
                 Perfect fourth 
                 1.334840:1 
               
               
                   
                 Augmented fourth/Diminished fifth 
                 1.414214:1 
               
               
                   
                 Perfect fifth 
                 1.498307:1 
               
               
                   
                 Minor sixth 
                 1.587401:1 
               
               
                   
                 Major sixth 
                 1.681793:1 
               
               
                   
                 Minor seventh 
                 1.781797:1 
               
               
                   
                 Major seventh 
                 1.887749:1 
               
               
                   
                 Octave 
                 2.000000:1 
               
               
                   
                   
               
            
           
         
       
     
     For example, if a reference frequency of 100 Hz is chosen, articulation networks may be deployed at octaves of 100 Hz, i.e., 200, 400, 800 Hz, etc. Additionally, articulation networks may be placed at fifths, i.e., 150 Hz, 300, 600 Hz, etc. 
     The articulation networks typically comprise a series RC network placed in parallel with the conductors of the host cable. The values of the articulation network&#39;s components are chosen such that the network has a desired Q profile at a desired frequency. In preferred embodiments, the Q is typically less than 1 at the target articulation frequency, and is typically less that the Q of the host cable at the cable&#39;s natural articulation point. 
     Additionally, the Q of the gang as a whole should be relatively constant throughout the audio spectrum. Typically, a cables&#39; articulation peak response is under-damped which may create undesirable ringing along with the presence and timbre issues related above. By adding the articulation networks the articulation response is not only broadened over a much wider range of frequencies but proper dampening is assured. 
     It is contemplated that the articulation networks may be employed in a variety of applications. For example, the networks may be formed from surface mount components and may of such a size as to be installed in the connectors of various electronic devices. In such embodiments, the components of the networks may be installed internally between the conductors of the connector. Such devices may include the RCA-type connectors typically found in home theater interconnect cables. 
     Additionally, the networks may be installed in any other two-port connector, such as ¼″ and ⅛″ connectors found in electronics devices. 
     It is contemplated that the networks may also be installed internal to the device itself. For example, the networks may be installed in the housing of headphones. In further embodiments, the networks may be installed in a coupling adaptor that is installed in-line between a source and destination of an electronic signal. 
       FIG. 2  is an assembly drawing of a networked connector  200  in accordance with the teachings of this disclosure. The exemplary embodiment of  FIG. 2  shows the networks of this disclosure being deployed internally to an RCA-type connector, but it is to be understood that the teachings of this disclosure may be employed in other types of connectors as well. 
       FIG. 2  shows the internal components of the networked connector  200 , including, from left to right, a center pin  210 , an insulator  220 , a printed circuit board (“PCB”) assembly  230 , a center guide insulator  240 , and a core funnel  250 . In an exemplary embodiment, the components of the networked connector  200  are circular in nature and arrange concentrically about an axis A. 
     The center pin  210  is formed from a conductive material and is adapted to be received by, and make an electrical connection with, a female RCA connector as is know in the art. The center pin  210  is generally cylindrically shaped about axis A and may include a front portion  211  that include a pair of tangs  211  formed therein that are configured to be deformed upon mating with a female connector, thereby maintaining electrical contact with the positive portion of the female receptacle while inserted. 
     The center pin  210  may also include a rear portion  213  that includes an internal bore  214 . The internal bore  214  is preferably includes a conically-shaped portion tapering inwards towards the forward portion  211  that is configured to receive and guide the center conductor of a coaxial cable to which the connector  200  is attached. The length and shape of the bore  214  is preferably shaped to maintain electrical contact with the center conductor. The center pin  210  may also include a retainer ring  215  disposed about the outer circumference on the center pin  210  proximate to the rear portion  213 . 
     The networked connector  200  also includes an insulator  220 , preferably formed from an electrical insulating material such as plastic or Teflon. The insulator  220  includes a forward portion  221  including a forward internal bore adapted to receive the center pin  210 . The insulator  220  also includes a rear portion  223  including a rear internal bore  224  adapted to receive the retainer ring  215 . The rear portion  223  may also include an outer shoulder  222  for receiving the printed circuit board assembly  230 . 
     The networked connector  200  also includes a center guide insulator  240 , preferably formed from an electrical insulating material such as plastic or Teflon. The center guide insulator  240  includes a forward portion  241  that has a forward internal bore  242  adapted to receive the rear portion  213  of the center pin  210 . The center guide insulator  240  also has a rear portion  243  that includes a pass-through bore  244  adapted to allow the center conductor of a coaxial cable to pass through to the inner bore  214  of the center pin  210 . 
     The networked connector  200  also includes a core funnel  250 , preferably formed from a conductive material as is known in the art. The core funnel  250  includes a forward portion  251  and a rear portion  256 . The forward portion  251  includes a front opening  257  defined in the forward surface of the forward portion  251 . The front opening  257  reveals a forward inner bore  253 . The forward inner bore  253  is adapted to receive the center guide insulator  240 , such that when inserted, the center guide insulator  240  is flush with the forward surface of the forward portion  251  of the core funnel  250 . The forward portion  251  may also include a shoulder portion  252  for abutting against the printed circuit board assembly  230 . 
     The core funnel  250  also includes a rear portion  256  that includes a rear opening  258  to a rear inner bore  254 . The opening  258  and rear inner bore  254  are adapted to receive a coaxial cable with the inner insulation that surrounds the center conductor exposed. The rear portion  256  of the core funnel  250  preferably includes a one or more conical step portions  255  for securing the outer braid shield of a coaxial cable around the core funnel  250  and maintaining a proper electrical ground contact. 
     The networked connector  200  also includes a PCB assembly  230 . The PCB assembly  230  is preferably is formed from a printed circuit board material as is known in the art in a disk shape as will be more fully detailed below. The PCB assembly  230  includes a front surface  232  that includes electrical components  231  installed thereon, and a back surface  233 . The PCB assembly  230  also includes an opening  234  adapted to fit around the exterior of the center pin  210 . 
     Referring now to  FIGS. 3-6 , an exemplary embodiment of a PCB assembly  230  and associated circuitry is shown. 
       FIG. 3  shows a side view of a PCB assembly  230  in accordance with the teachings of this disclosure.  FIG. 3  shows the front side  232  and components  231  connected thereon, and the back side  233  of the PCB assembly  230 . 
       FIG. 4  is a view of the back side  233  of the PCB assembly  230 . In exemplary embodiments, the back side  233  is adapted to function as the ground or negative connection for the electrical components  231  through a conductive area disposed as an outer radial ground plane  530  proximate to the outer radial area of the disk-shaped printed circuit board. The ground plane  530  may also include pass-through conductive paths  235  for electrically connecting the electrical components  231  on the front side  232  to the ground plane  530 . 
       FIG. 4  also shows an inner positive connection ring  236  for connecting the electrical components  231  to a positive electrical connection. It is contemplated that conductive material is disposed about an inner surface defined by the opening  234  so as to make electrical contact with the center pin  210  when assembled as described more fully below. An insulating area  237  preferably separates the ground plane area  530  and the positive connection ring  236 . 
     Referring now to  FIG. 5 , an exemplary circuit  500  is shown in schematic form. The circuit  500  includes a positive connection  510  and a negative connection  520 . In the schematic of  FIG. 5 , three circuit branches are shown, each branch comprising a capacitor and resistor in series. A first branch includes a capacitor C 1  connected in series with a resistor R 1 , a second branch includes a capacitor C 2  connected in series with a resistor R 2 , and third branch includes a capacitor C 3  connected in series with a resistor R 3 . The first, second, and third branches are electrically coupled together in parallel between the positive connection  510  and negative or ground connection  520 . 
     It is to be understood that many other circuit topologies are within the scope of the present disclosure, and the disclosed circuit is intended to be illustrative only. It is contemplated that the articulation networks embodiments disclosed herein may be embodied in the networked connector of this disclosure. 
       FIG. 6  shows the front surface  235  of the PCB assembly, illustrating how the exemplary circuit  500  may be embodied in accordance with the teachings of this disclosure. For illustrative purposes, the connection of the capacitor C 3  and resistor R 3  will be shown; the other branches of the circuit  500  are connected in a similar manner. 
     In  FIG. 6 , the capacitors and resistors may comprise surface mount components formed as is known in the art on the front surface  232  of the PCB assembly  230 . It is contemplated that any electrical component suitable in size to be installed within the desired connector assembly may be employed herein. 
     Capacitor C 3  is show being connected between to the positive connection through the positive center ring  236  at node  239 , and to resistor R 3  via a conductive path  238 , which may be formed on the front surface  232 . Resistor R 3  is shown being connected to C 3  through path  238  and to the ground plane  530  on the back side  233  through pass-through connector  235 . 
     As will now be appreciated from the topology of  FIG. 6 , all branches of the circuit  500  are connected to a common positive connection via the inner positive connection ring  236 , and the negative or ground connections are accomplished via the pass-through connections to the ground plane  530  on the back side  233  of the PCB assembly  230  to form a common ground. 
     Referring now to  FIG. 7 , a cross-sectional assembly diagram of networked connector  700  is shown.  FIG. 7  shows the networked connector of  FIGS. 2-6  assembled along the axis A and affixed together using an RCA connector head  710 . The RCA head  710  includes flanges  760  for making the electrical ground connection to a female RCA connector to which the networked connector  700  is attached, and threads  750  for receiving an RCA body portion (not shown). 
     To assemble the networked connector, the following process may be employed, beginning with the center pin  210 . 
     Center pin  210  is inserted through the rear portion  223  of the insulator  220 , until the retainer ring  215  is firmly seated within the rear inner bore  224 . The PCB assembly  230  may be slid over the rear portion  213  of the center pin  210 . When seated, the inner positive connection ring  236  is brought into electrical contact with the outer surface of the center pin  210  at areas  740 , forming a positive connection for the circuit components  231 . 
     The center guide insulator  240  is then placed on the rear portion  213  of the center pin  210 , and the cone funnel  250  is placed over the center guide insulator  240 . The forward portion  251  of the cone funnel  250  is then brought into contact with the back surface  233  of PCB assembly  230 . The ground plane  530  is therefore brought into electrical contact with the shoulder portion  252  and thus the cone funnel  250 . 
     To secure the various parts of the networked connector  700  together, the RCA head  710  may have a portion crimped over the shoulder portion  252  to form a crimp connection  730 . The compressive action of the crimp  730  forces the PCB assembly  230  against the retainer ring  215 , and the shoulder portion  252  against the ground plane  530  on the back side  233  of the PCB assembly  230 . In such a manner, the electrical connection through the circuitry  231  is maintained in an effective fashion. 
     When installed on the end of a cable, the center conductor of the cable will be inserted through the opening  258  and into the inner bore  214  of the center pin  210 . The ground conductor, typically the braid shield of the cable, will be connected to the rear portion  256  of the cone funnel  250 . Thus, the circuitry  231  will be electrically coupled between the center conductor and ground connection of the cable through the center pin  210  and cone funnel  250 , respectively. 
     It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character thereof. The foregoing description is therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all changes which come within the meaning and range of equivalents thereof are intended to be embraced therein.