Abstract:
A method is provided for determining a modulation of a CATV channel, the modulation being one of a digital modulation and an analog modulation. The method includes passing at least a portion of a tuner output from a tuner to a RF detector, and passing a RF detector output from the RF detector to a sync detector. The method further includes attenuating at least a portion of a sync detector output to create a remaining portion of the sync detector output, and passing the remaining portion of the sync detector output to a peak detector. The method further includes passing an output of the peak detector to a subsequent device, the output of the peak detector indicating whether the modulation of the CATV channel.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to level measurement and comparison devices for use in community antenna television (“CATV”) systems, and in particular to level measurement and comparison devices for use in CATV systems including content being passed using an analog modulation and content being passed using a digital modulation. 
     BACKGROUND OF THE INVENTION 
     The use of a CATV system to provide internet, voice over internet protocol (“VOIP”) telephone, television, security, and music services is well known in the art. In providing these services, a downstream bandwidth (i.e., radio frequency (“RF”) signals, digital signals, and/or optical signals) is passed from a supplier of the services to a user, and an upstream bandwidth (i.e., radio frequency (“RF”) signals, digital signals, and/or optical signals) is passed from the user to the supplier. For much of the distance between the supplier and the user, the downstream bandwidth and the upstream bandwidth make up a total bandwidth that is passed via a signal transmission line, such as a coaxial cable. The downstream bandwidth is, for example, signals that are relatively higher in frequency within the total bandwidth of the CATV system while the upstream bandwidth is, for example, signals that are relatively lower in frequency. 
     Traditionally, the CATV system includes a head end facility, where the downstream bandwidth is initiated into a main CATV distribution system, which typically includes a plurality of trunk lines, each serving at least one local distribution network. In turn, the downstream bandwidth is passed to a relatively small number (e.g., approximately 100 to 500) of users associated with a particular local distribution network. Devices, such as high-pass filters, are positioned at various points within the CATV system to ensure the orderly flow of downstream bandwidth from the head end facility, through the trunk lines, through the local distribution networks, and ultimately to the users. 
     At various locations between the head end facility and the user, there are amplifiers and slope adjustment devices for the purpose of maintaining the quality of the downstream bandwidth. This statement introduces three terms (i.e., quality, amplifiers, and slope adjustment devices) that are important to the remaining discussion. These will be discussed broadly below. 
     The quality of the downstream bandwidth is often a measure of: (i) a signal level of a particular channel within the downstream bandwidth, the signal level referred to merely as “level;” and (ii) a general consistency of levels across all of the channels in the downstream bandwidth, the general consistency referred to as “slope.” These objective measurements are often used by technicians to evaluate CATV system performance during operation and to troubleshoot customer complaints. 
     The level of each channel should fall within a specific range that has been determined to provide satisfactory video, sound and information transfer rates for users. The specific requirements for each channel are not of importance to the present discussion, but it is helpful to understand that there are specific targets for the level of each channel. Note that this is a simplistic definition to explain “level,” and note that this definition does not include other variances such as between analog and digital. 
     Slope is a measurement used to assess the amount of loss experienced due in large part to cable length. While all channels experience some loss, channels transmitted using higher frequencies within the downstream bandwidth experience more loss than those transmitted using lower frequencies. Accordingly, when the levels for all of the channels within the downstream bandwidth are graphed such that they are arranged in order according to the frequency of the channel, there may be a significant visual downward slope in the graph from the lowest frequency channel to highest frequency channel. This downward slope becomes more prominent as the length of signal cable increases. Note that this is a simplistic definition to explain the consistency of levels across all of the channels and the “slope” that is created by losses occurring in the signal cables. Also note that this definition does not include other variances such as between analog and digital. 
     For at least the forgoing reasons, a need is apparent for a device, which can accurately measure the level of channels present in the downstream bandwidth and accurately compare these measurements to determine whether amplification is required and whether slope adjustment is required. 
     SUMMARY OF THE INVENTION 
     The present invention helps to increase the quality of the downstream bandwidth. Increasing the quality of the downstream bandwidth improves customer satisfaction and reduces expenditures relating to customer complaints. 
     In accordance with one embodiment of the present invention, a modulation analyzer and level measurement device is provided for use with a CATV system. The device includes, a tuner, a band pass filter connected electrically downstream the tuner, and an RF detector connected electrically downstream the band pass filter. The device further includes a sync detector connected electrically downstream the RF detector, and a peak detector connected electrically downstream the sync detector. 
     In accordance with one embodiment of the present invention, a method is provided for determining a modulation of a CATV channel. The modulation being one of a digital modulation and an analog modulation. The method includes passing at least a portion of a tuner output from a tuner to a RF detector, and passing a RF detector output from the RF detector to a sync detector. The method further includes attenuating at least a portion of a sync detector output to create a remaining portion of the sync detector output, and passing the remaining portion of the sync detector output to a peak detector. The method further includes passing an output of the peak detector to a subsequent device, the output of the peak detector indicating whether the modulation of the CATV channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the nature and objects of the invention, references should be made to the following detailed description of a preferred mode of practicing the invention, read in connection with the accompanying drawings in which: 
         FIG. 1  is a circuit diagram representing a downstream device including a downstream section made in accordance with one embodiment of the present invention; 
         FIG. 2  is a representation of a frequency domain voltage stream of a channel having an analog modulation; 
         FIG. 3  is a representation of a frequency domain voltage stream of a channel having a digital modulation; 
         FIG. 4  is a representation of a voltage stream output (analog) from a band-pass filter arranged in accordance with an embodiment of the present invention; 
         FIG. 5  is a representation of a voltage stream output (digital) from a band-pass filter arranged in accordance with an embodiment of the present invention; 
         FIG. 6  is a representation of a time domain voltage stream (analog) from a RF detector arranged in accordance with one embodiment of the present invention; 
         FIG. 7  is a representation of a time domain voltage stream (digital) from a RF detector arranged in accordance with one embodiment of the present invention; and 
         FIG. 8  is a representation of a voltage stream (analog) from a sync detector arranged in accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a measurement device  100  may include an RF connector  110 , which may be any of the connectors used in the art for connecting a signal cable to a device. For example, the RF connector  110  may be a traditional “F-type” connector. 
     The term “connected” is used throughout to mean optically or electrically positioned such that current, voltages, and/or light are passed between the connected components. It should be understood that the term “connected” does not exclude the possibility of intervening components or devices between the connected components. For example, the tuner  130  is connected to the RF connector  110  even though a fixed signal level adjustment device  140  is shown to be positioned in an intervening relation between the tuner  130  and the RF connector  110 . 
     The fixed signal level adjustment device  140  may be positioned between the RF connector  110  and the tuner  130 . The fixed signal level adjustment device  140  may be used to prevent the RF connector  110  from drawing too much power from a connected source. Further, the fixed signal level adjustment device  110  may be sized to provide the tuner  130  with the coupled downstream bandwidth having an appropriate amount of power for the tuner  130  and subsequent devices. Accordingly, one skilled in the art would understand, based on the present disclosure, whether the fixed signal level adjustment device  140  is required and what size of the fixed signal level adjustment device  140  is required for any particular RF connector  110  and tuner  130  combinations. 
     The tuner  130  is a traditional tuner device that can be “tuned” to selected channels based on an input from a microprocessor  120 . In particular the tuner  130  used in the present embodiment is provided with a target index number (Index #) that corresponds with CATV channels, as shown below in Table 1. The purpose for pointing out these index numbers is to show that CATV channels have not been introduced in an orderly fashion. For example, CATV channel 95 (Index # 5) is lower in frequency than CATV channel 14 (Index #10). Accordingly, the present microprocessor  120  controls the tuner  130  based on an index number that increments in ascending order along with the frequencies that the index number represents. If a more powerful microprocessor and/or a more complex software control are used, the index of channels, shown below, may not be necessary. 
     
       
         
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Channel Bandwidth 
                   
               
             
          
           
               
                   
                 Index # 
                 Channel Designator 
                 Low end 
                 High End 
               
               
                   
                   
               
             
          
           
               
                   
                 0 
                 2 
                 54 
                 60 
               
               
                   
                 1 
                 3 
                 60 
                 66 
               
               
                   
                 2 
                 4 
                 66 
                 72 
               
               
                   
                 3 
                 5 
                 76 
                 82 
               
               
                   
                 4 
                 6 
                 82 
                 88 
               
               
                   
                 5 
                 A-5 (95) 
                 90 
                 96 
               
               
                   
                 6 
                 A-4 (96) 
                 96 
                 102 
               
               
                   
                 7 
                 A-3 (97) 
                 102 
                 108 
               
               
                   
                 8 
                 A-2 (96) 
                 108 
                 114 
               
               
                   
                 9 
                 A-1 (99) 
                 114 
                 120 
               
               
                   
                 10 
                 A (14) 
                 120 
                 126 
               
               
                   
                 11 
                 B (15) 
                 126 
                 132 
               
               
                   
                 12 
                 C (16) 
                 132 
                 138 
               
               
                   
                 13 
                 D (17) 
                 138 
                 144 
               
               
                   
                 14 
                 E (18) 
                 144 
                 150 
               
               
                   
                 15 
                 F (19) 
                 150 
                 156 
               
               
                   
                 16 
                 G (20) 
                 156 
                 162 
               
               
                   
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
               
               
                   
                 94 
                 C91 
                 624 
                 630 
               
               
                   
                 95 
                 C92 
                 630 
                 636 
               
               
                   
                 96 
                 C93 
                 636 
                 642 
               
               
                   
                 97 
                 C94 
                 642 
                 648 
               
               
                   
                 98 
                 C100 
                 648 
                 654 
               
               
                   
                 99 
                 C101 
                 654 
                 660 
               
               
                   
                 100 
                 C102 
                 660 
                 666 
               
               
                   
                 101 
                 C103 
                 666 
                 672 
               
               
                   
                 102 
                 C104 
                 672 
                 678 
               
               
                   
                 103 
                 C105 
                 678 
                 684 
               
               
                   
                 104 
                 C106 
                 684 
                 690 
               
               
                   
                 105 
                 C107 
                 690 
                 696 
               
               
                   
                 106 
                 C108 
                 696 
                 702 
               
               
                   
                 107 
                 C109 
                 702 
                 708 
               
               
                   
                 108 
                 C110 
                 708 
                 714 
               
               
                   
                 109 
                 C111 
                 714 
                 720 
               
               
                   
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
               
               
                   
                   
               
             
          
         
       
     
     The term “microprocessor” used throughout should be understood to include all active circuits capable of performing the functions discussed herein. For example, the microprocessor  120  may be replaced with a microcontroller, a system specific digital controller, or a complex analog circuit. 
     The output voltage stream from the tuner  130  is typical of tuners in that the voltage stream is a single channel output spectrum voltage stream, which in the case of NTSC is 6 MHz. If the output voltage stream from the tuner  415  is an analog modulation, the spectrum will likely appear as shown in  FIG. 2 , which will be described in further detail below. If the output voltage stream from the tuner  415  is a digital modulation, the modulation will likely appear as shown in  FIG. 3 . 
     Referring  FIG. 2 , an analog modulation spectrum  270  includes, in relevant part, a sound subcarrier  272  (“SOX  272 ”), a color subcarrier  274  (“CLX  274 ”), and a picture subcarrier  276  (“PIX  276 ”). Note that other parts or subcarriers may be present or may be missing from the single channel output spectrum voltage stream, as various signal formats are different in accordance with differing standards. As is shown in  FIG. 2 , a total integrated power in the analog modulation spectrum  270  is not evenly distributed. Rather, the PIX  276  represents approximately 50% of the total power in the analog modulation spectrum  270 . Further, the integrated power between the PIX  276  and the CLX  274  varies with the content of any picture being output from the tuner  130 . However, a vertical synchronization portion  278  (“vertical sync  278 ”) and a horizontal synchronization portion  280  (“horizontal sync  280 ”) of the analog modulation spectrum  270  are located very near the PIX  276  and remain at a nearly constant power level. The SOX  272 , typically transmitted at −15 dBc (decibels below carrier) also remains at a nearly constant power level because it is frequency modulated. The lowest powered subcarrier is the CLX  274 , typically transmitted at −20 dBc, also remains at a nearly constant power level because it is phase modulated. Based on these ratios, the CLX  274  represents approximately 1% of the total power, and the SOX represents approximately 4.5% of the total power. 
     Referring now to  FIG. 4 , a digital modulation spectrum  282  has an evenly distributed integrated power transmitted at −10 dBc from an equivalent analog modulated carrier. 
     Referring back to  FIG. 1 , a relatively narrow band-pass filter  150  may be electrically connected to an output of the tuner  130 . The band-pass filter  150  removes extraneous signals above and below desired frequencies, which in the present embodiment is the PIX  276  ( FIG. 2 ) provided by the tuner  130 . Alternatively, the band-pass filter  150  may be replaced by a narrow low-pass filter, as the vertical synchronization frequency is modulated low within the range of frequencies in accordance with NTSC. Similarly, the band-pass filter  150  may be replaced by a high-pass filter that removes extraneous signals below other desired frequencies provided by the tuner, such as the horizontal synchronization frequency. It should be understood that differing frequencies may need to be selected depending on the analog modulation scheme expected. A resulting frequency domain voltage stream is then passed to an RF detector  160 . 
     A resulting frequency domain voltage stream  284  (“analog voltage stream  284 ”) ( FIG. 4 ) is expected to pass from the band-pass filter  150  when the analog modulation spectrum  270  is provided by the tuner  130 , and a resulting frequency domain voltage stream  286  (“digital voltage stream  286 ”) ( FIG. 5 ) is expected to pass from the band-pass filter  150  when the digital modulation spectrum  282  is provided by the tuner  130 . While there is a significant power difference between the analog voltage stream  284  and the digital voltage stream  286 , this difference may not be sufficient to accurately discriminate between the analog voltage stream  284  and digital voltage stream  286 , especially because the incoming signal level of the individual channels may vary greatly. Accordingly, additional means, discussed more fully below, are provided to discriminate between the analog voltage stream  284  and digital voltage stream  286 . 
     The RF detector  160  converts the frequency domain voltage stream passed from the band-pass filter  150  into a time domain voltage stream (analog)  292  ( FIG. 6 ) or (digital)  294  ( FIG. 7 ). More specifically, the RF detector  160  performs the effect of an inverse Laplace, the Laplace transform being a widely used integral transform, to convert the portion of the downstream bandwidth from a frequency domain voltage stream into a time domain voltage stream. The inverse Laplace transform is a complex integral, which is known by various names, the Bromwich integral, the Fourier-Mellin integral, and Mellin&#39;s inverse formula. An alternative formula for the inverse Laplace transform is given by Post&#39;s inversion formula. Accordingly, any other device capable of such a conversion from the frequency domain to the time domain may be used in place of the RF detector  160 . Afterward, the time domain voltage stream  292 ,  294  is passed to both a synchronization detector  170  (“sync detector  170 ”) and a low frequency level detector  180 . 
     The time domain voltage stream  292 ,  294  differs depending on whether the frequency domain voltage stream is the analog voltage stream  284  or the digital voltage stream  286 . For example,  FIG. 6  is a typical baseline time domain signal voltage stream (analog)  292  from the RF detector  160  when the analog voltage stream  284  is passed to the RF detector  160 . As shown in  FIG. 6 , a very large portion of the time domain voltage stream (analog) includes vertical synchronization pulses  288  and horizontal synchronization pulses  290 . Accordingly, the time domain voltage stream (analog)  292  relative to the analog voltage stream  284  includes distinct and large components that have specific time periods. 
     The voltage stream represented in  FIG. 7  is the typical baseline time domain voltage stream (digital)  294  from the RF detector  160  when the digital voltage stream  286  is passed to the RF detector  160 . As shown in  FIG. 7 , the time domain voltage stream (digital)  294  includes none of the distinctive attributes present in the time domain voltage stream (analog)  292 , such as components having specific time period and specific amplitude relationships. 
     The sync detector  170  attempts to extract timing information from the time domain voltage stream  292 ,  294 . For example, with the time domain voltage stream (analog)  292  (generated from the analog voltage stream  284 ) the sync detector  170  extracts the vertical sync  278  and the horizontal sync  280 , and the sync detector  170  provides a sync detector voltage stream (analog)  296  represented in  FIG. 8 . In the present embodiment, the sync detector voltage stream (analog)  296  has a period of 16.8 milliseconds and a duty cycle of 1.37%. Further, the sync detector output  296  results in a fundamental frequency of 59.5 Hz with harmonics starting above 4300 Hz, which means that a significant amount of energy resides in the fundamental frequency of 59.5 Hz. These values are optimal, but other values are possible. 
     In contrast to the sync detector voltage stream (analog)  296 , a sync detector voltage stream (digital) from the sync detector  170  is either high or low and randomly flips back and forth at a rate of less than 5 seconds, in the present embodiment, when the digital voltage stream  286  is passed into the sync detector  170 . More specifically, the energy present in the sync detector voltage stream (digital) resulting from the digital voltage stream  286  is randomly distributed among the frequencies that are well below 0.2 Hz. Accordingly, the sync detector  170  generates a significant amount of time domain separation between the sync detector voltage stream (analog)  296  and the sync detector voltage stream (digital) in the output of the sync detector  170 . 
     The sync detector output (either analog or digital) is then passed to a low-pass filter  190 . The low-pass filter  190  is provided having a low frequency zero caused by an input blocking capacitor. This arrangement removes frequencies well below 59.5 Hz and frequencies above 300 Hz leaving only the fundamental vertical sync frequencies. Accordingly, when the sync detector  170  provides the sync detector voltage stream (digital), the low-pass filter  190  passes essentially no energy to a peak detector  195  connected electrically downstream the sync detector  170 . These values are optimal, but other values are possible. 
     The peak detector  195  produces a relatively consistent voltage stream when the sync detector  170  and the low-pass filter  190  provide a voltage stream including synchronous voltages. In the presence of a voltage stream including random, non-synchronous voltages, which is the case in the presence of the sync detector voltage stream (digital), the peak detector  195  is unable to produce a voltage steam that is consistently a significant voltage above ground. Accordingly, the peak detector  195  remains in a low logic state in the presence of the sync detector voltage stream (digital). Alternatively, when portions of the sync detector voltage stream (analog)  296  are passed from the low-pass filter  190 , the peak detector  195  sees significant amounts of energy, and the peak detector  195  changes to a high logic state. The peak detector  195  may also be referred to as a level detector and/or an integrator performing a similar function. 
     A resulting voltage stream from the peak detector  195  is input along a path  200  into the microprocessor  120  as a signal that discriminates between analog modulation channels and digital modulation channels. More specifically, the voltage stream from the peak detector  195  indicates that the tuner  130  is tuned to an analog modulation channel when the voltage stream is consistently a significant voltage above ground. Conversely, the voltage stream from the peak detector  195  indicates that the tuner  130  is tuned to a digital modulation channel when the voltage steam is consistently near ground. Alternatively, the peak detector  195  may be an inverting peak detector. When such an inverting peak detector is used, the voltage stream would be a significant voltage below the power supply rail when the tuner  130  is tuned to an analog modulation channel. 
     As mentioned above, the voltage stream from the RF detector  160  is also passed to the low frequency level detector  180  and an integration capacitor (not shown) connected electrically between the low frequency level detector  180  and a DC shift amplifier  185 . The low frequency level detector  180  and integration capacitor are used to integrate the total power of the voltage stream coming out of the RF detector  160 . For example, a digital modulation is −10 dBc in relation to the analog PIX  276 , the power in the two types of modulations (analog and digital) is equal. Accordingly, the detected voltage at the integration capacitor is similar between the two types of modulations (i.e., analog and digital). The voltage stream from the low frequency level detector  180  and integration capacitor is then input into the DC shift amplifier  185 . The low frequency level detector  180  may also be known as a peak detector. 
     The DC shift amplifier  185  may be used as a low pass amplifier to provide a voltage stream that has been shifted in scale by a known amount to render the signal voltages appropriate for the microprocessor  120 . The amount of voltage shift and/or amplification is determined by a voltage source  155  connected to the DC shift amplifier  185  by an adjustable attenuator  165 . Accordingly, the DC shift amplifier  185  may also be known as a low-pass amplifier. A portion of the voltage stream from the DC shift amplifier  185  is passed back to an automatic gain control input of the tuner  130  that adjusts a total system gain. This voltage stream holds the tuner output at a constant level. Additionally, a portion of the voltage stream from the DC shift amplifier  185  is passed to a high-gain amplifier  175 , and a portion of the voltage stream from the DC shift amplifier  185  is passed to a low-gain amplifier  205 . 
     The high-gain amplifier  175  is provided with the voltage stream from the DC shift amplifier  185  to function as a voltage comparator. For example, if any DC voltage shift is sensed at the output of the integration capacitor, from a DC voltage representing no input signal to the tuner, the high-gain amplifier  175  saturates and stays at a low side voltage power supply rail. Accordingly, this arrangement effectively makes a digital output that is high when there is no signal or channel, and low when there is any signal or channel. This arrangement provides a voltage stream in a path  210  to the microprocessor  120  to identify the occurrence of a transmitted channel present at the Index # tuned by the tuner  130 . Alternatively, the high-gain amplifier  175  may be inverting high-gain amplifier. When an inverting high-gain amplifier is used, the voltage stream would low when there is no signal or channel, and high when there is any signal or channel. 
     The low-gain amplifier  205  is also provided with the voltage stream from the DC shift amplifier  185 . The low-gain amplifier  205  is shifted in response to the voltage source  215 , which is connected to the low-gain amplifier  205  via an adjustable attenuator  220 . The gain of low-gain amplifier  205  is only large enough to cause the low-gain amplifier  205  to reach a positive voltage rail when an input voltage stream is at a high end of the allowable range of the input voltage stream. The resulting voltage stream from the low-gain amplifier  205  is relative to the level of the channel at the tuned index and is sufficient for the provision of the relative level to the microprocessor  310 . Further, the low-gain amplifier  205  scales the level of the channel at the tuned index for maximum resolution with respect to the microprocessor  120 . The voltage source  215  is used to calibrate a range of the low-gain amplifier  205  through adjustment of the adjustable attenuator  220 . Accordingly, the voltage stream provided in a path  225  to the microprocessor  120  is used to identify the level of a transmitted channel present at the Index # tuned by the tuner  120 . 
     The measurement device  100  may first be calibrated to provide a more accurate output to a laptop computer  230  or other output device. The calibration is accomplished by attaching the measurement device  100  to a matrix generator, which provides the measurement device  100  with at least two known levels, such as 0 dBmV and 20 dBmV, at every index number. The calibration sequence proceeds with the tuner  130  incrementing through each index number (from the chart provided above) and obtaining a calibration level for each index number. In the present embodiment, this calibration level is saved as a digital value between 0 and 255. The following is a chart of sample calibration levels, the values being chosen for exemplary purposes only: 
     
       
         
               
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 Calibration Level 
               
             
          
           
               
                 Index # 
                 Channel Designator 
                 Low end 0 dBmV 
                 High End 20 dBmV 
               
               
                   
               
             
          
           
               
                 0 
                 2 
                 155 
                 210 
               
               
                 1 
                 3 
                 165 
                 225 
               
               
                 2 
                 4 
                 155 
                 218 
               
               
                 3 
                 5 
                 160 
                 223 
               
               
                 4 
                 6 
                 155 
                 214 
               
               
                 5 
                 A-5 (95) 
                 148 
                 205 
               
               
                 6 
                 A-4 (96) 
                 168 
                 224 
               
               
                 7 
                 A-3 (97) 
                 168 
                 231 
               
               
                 8 
                 A-2 (96) 
                 159 
                 217 
               
               
                 9 
                 A-1 (99) 
                 163 
                 224 
               
               
                 10 
                 A (14) 
                 168 
                 226 
               
               
                 11 
                 B (15) 
                 150 
                 213 
               
               
                 12 
                 C (16) 
                 163 
                 226 
               
               
                 13 
                 D (17) 
                 167 
                 224 
               
               
                 14 
                 E (18) 
                 167 
                 228 
               
               
                 15 
                 F (19) 
                 161 
                 224 
               
               
                 16 
                 G (20) 
                 149 
                 220 
               
               
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
               
               
                 94 
                 C91 
                 163 
                 231 
               
               
                 95 
                 C92 
                 166 
                 220 
               
               
                 96 
                 C93 
                 162 
                 219 
               
               
                 97 
                 C94 
                 148 
                 208 
               
               
                 98 
                 C100 
                 175 
                 218 
               
               
                 99 
                 C101 
                 162 
                 212 
               
               
                 100 
                 C102 
                 163 
                 211 
               
               
                 101 
                 C103 
                 172 
                 235 
               
               
                 102 
                 C104 
                 172 
                 231 
               
               
                 103 
                 C105 
                 158 
                 202 
               
               
                 104 
                 C106 
                 162 
                 218 
               
               
                 105 
                 C107 
                 151 
                 209 
               
               
                 106 
                 C108 
                 161 
                 217 
               
               
                 107 
                 C109 
                 163 
                 213 
               
               
                 108 
                 C110 
                 168 
                 215 
               
               
                 109 
                 C111 
                 159 
                 216 
               
               
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
                 ~ . . . 
               
               
                   
               
             
          
         
       
     
     Even though two calibration values are shown below for each channel, it is possible to use only one calibration value for each, with at least one assumption. For example, one calibration value only may be used if/when an assumed increment is used for voltage changes. 
     After the measurement device  100  is calibrated for use, the measurement device  100  may be attached at any location within a CATV system. The use and control of the measurement device may take a variety of different forms, a few of which will be outlined below. 
     One such use includes a technician entering a particular Index # or other channel identifier into the laptop computer  230  (or any other handheld or larger device). The measurement device  100  then provides channel information to the technician. This channel information may include: (i) whether a channel is present; (ii) whether the channel is being received in an analog or digital modulation, and (iii) the level of the channel being received. The technician may choose to review the provided information on a display screen and then act upon the information to attach and/or adjust signal conditioning equipment. The provided information may also be saved to a computer readable medium for review, data analysis and action such as the issuance of control system operational instructions based on the information, at a later date or on a more system wide basis. 
     Another such use includes a technician running a routine that samples channels at predetermined positions across the CATV transmission spectrum. In this example, the measurement device  100  may provide channel information relating to groups of channels for the purpose of making comparisons between the channels. As with above, this channel information may include: (i) whether the selected channels are present; (ii) whether the selected channels are being received in an analog or digital modulation, and (iii) the level of each channel being received. The technician may choose to review the provided information on a display screen and then act upon the information to attach and/or adjust signal conditioning equipment. The provided information may also be saved to a computer readable medium for review, data analysis and action such as the issuance of control system operational instructions based on the information, at a later date or on a more system wide basis. 
     Another such use includes incorporating the measurement device into a downstream bandwidth conditioning device that is used to condition the downstream bandwidth in terms of level and slope. Within such a device, the microprocessor  120  may increment the tuner  130  through at least two channels to determine an appropriate amount of level and slope adjustment to apply as part of the conditioning process. 
     While not explicitly shown in  FIG. 1 , the measurement device  100  may be remotely mounted from the laptop computer  230  (or any other handheld or larger device), such that the information provided to and from the microprocessor  120  is transmitted by any one of the know information transmission technologies, including, but certainly not limited to, DOCSIS, TCP/IP, RS232, and 802.11. Along these lines, it is envisaged that a plurality of measurement devices  100  may by placed at various locations around a CATV systems while being accessed by a single laptop computer  230  or other remote storage device, enabling individual user, group and broader system-wide analysis of operational parameters. It is envisaged that such analysis may lead to observation and the postulation of control instructions to optimize system operation for an individual user or group of cable subscribers. 
     While the present invention has been particularly shown and described with reference to certain exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by claims that can be supported by the written description and drawings. Further, where exemplary embodiments are described with reference to a certain number of elements it will be understood that the exemplary embodiments can be practiced utilizing either less than or more than the certain number of elements.