Tektronix DC503A Universal Counter/Timer

Back to Tek TM500 Series Summary Page

Quick Specifications / Photos
List of Options
Detailed Specifications
Operating Instructions
Misc. Part Numbers

Samples of e-Bay Prices
Tektronix Catalog CostLow BidHigh Bidaverage
$930 (1982)
$1165 (1985)
3022799
$61.00 7/27/01 #1619000143 bbg
no sale ($82 < reserve) 8/10/01 #1624260692 dogchow (with DP501)
$139.50 8/16/01 #1625854306 jshank
$46.00 8/23/01 #1628143440 calibrat1
$82.55 9/1/01 #1630447181 rhinoenter
$102.50 9/10/01 #1634609077 rhinoenter
$161.00 9/20/01 #1638374083 jshank
$45.00 10/13/01 #1645755324 fredrichelectronics
$45.00 11/10/01 #1657539268 ba3
$40.60 11/14/01 #1660861860 ridgeeq
$53.04 12/4/02 #1921607964 j.a.
$36.00 12/23/02 #3100880412 jbarkley@vnet.com (12 bids)
$11.61 5/25/05 #7517402435 jtsele (2 bids $9.99 start) (working-guaranteed)
$56.00 12/29/05 #7574905239 longbeard4m1m (12 bids $0.99 start) (was working)
$67.98 4/7/06 #7605956922 mikeb61 (2 bids $58 start) (tested-functioning well)
$49.99 (+~$41 ship from australia) 7/10/07 #110145743053 the-macservice-group (1 bid) (powered up)
#103.50 (+$24.95 ship) 7/18/07 #220130081651 anainstr (11 bids $10 start) (working-display shown)
$43.53 (+? ship) 8/3/08 #120288292848 sx28 (4 bids $24.99 start) (powers up works fine)

QUICK SPECS / PHOTOS
  • 2 Input Channels
  • 125MHz capability on each channel.
  • 8-digit readout
    Use P6106A Probe

    The DC 503A offers a broad range of measurement features. The instrument has two input channels, A and B, each with 125 MHz capability. Each channel has separate triggering level, triggering slope, attenuator, and coupling mode controls. Eight measurement functions are available with the DC503A, and an averaging feature allows averaging of 1 to 10 occurrence of the signal of interest. Signals to be counted or timed can be applied to channels A and B via the front panel BNC connector or through the rear interface connection. The DC503A features an easy to access front panel and an LSI-based design for increased instrument reliability.

    LIST OF OPTIONS
    Option 1 = Replaces the internal 10 MHz time base (clock) circuit with a self-contained proportional temperature controlled oven oscillator for increased accuracy and stability.

    SPECIFICATIONS

    The DC 503A Universal Counter/Timer is designed to operate in a TM 500-series power module.

    The instrument has two input channels, CH A and CH B, each with 125 MHz capability. Each channel has separate triggering level, triggering slope, attenuator, and coupling mode controls.

    The DC 503A has eight measurement functions: FREQUENCY A, PERIOD B, WIDTH B, TIME A-B, RATIO A/B, EVENTS A DURING B, TOTALIZE A, and TIME MANUAL. All of the modes except FREQUENCY A, TOTALIZE A, and TIME MANUAL have the capability of averaging the selected measurement over a range of 1 to 10(exp 8) times the input signal. The signals to be counted or measured can be applied via front panel bnc connectors or throught the rear interface.

    The triggering level for each channel can be monitored via the front panel or the rear interface connections. The buffered voltage available at these connectors corresponds to the trigger levels set by the front panel controls.
    The output of the internal signal shaping ciruits can also be monitored via front panel connectors. These shaped signal outputs are useful in setting the triggering points on complex waveforms.

    Measurement results are displayed in an eight digit LED readout. The decimal point is automatically positioned and leading zeros are blanked. Single annunciators (LEDs) are used to indicate register overflow, active gating interval, and the frequency or time units associated with the measurement being made.

    The DC 503A can be equipped with an optional, oven controlled, 10 MHz crystal oscillator to obtain a highly stable and precise internal time base. Both the optional oscillator and the standard 10 MHz time bases provide 100 ns single shot resolution.

    ELECTRICAL CHARACTERISTICS

    CharacteristicsPerformance RequirementsSupplemental Information
    CH A and CH B INPUTS/OUTPUTS
    Input Frequency Range
    Front Panel
    DC Coupled
    0 Hz to >= 125 MHz.
    AC Coupled
    10 Hz to >= 125 MHz.
    Rear Interface
    DC Coupled
    0 Hz to >= 50 MHz.
    AC Coupled
    10 Hz to >= 50 MHz.
    Input Sensitivity
    X1 Attenuation
    20 mV rms sine wave to 100 MHz.
    35 mV rms sine wave to 125 MHz.
    60 mV peak-to-peak pulse at a minimum pulse width of 5 ns to 100 MHz.
    100 mV peak-to-peak pulse at a minimum pulse width of 4 ns to 125 MHz.
    X5 Attenuation Accuracy
     <= 2% at dc.
    Input Dynamic Range
    X1 Attenuation
     <= 3V, peak-to-peak
    X5 Attenuation
     <= 15V, peak-to-peak
    Shaped Outputs
    Delay From Front Panel
     Typically 15 ns.
    Output Voltage Levels
     >= 100 mV into 50 Ω, >= 200 mV unterminated.
    Trigger Level
    Range
    ± 3.5 V times attenuation
    Slope
    Plus (+) or minus (-)Independently selectable.
    Output Accuracy
    ± 20 mV ± 0.5% of reading
    Input Impedance
    Front Panel
    X1, X5 Attenuation
     1 MΩ, shunted by approximately 27 pf.
    (-13V <= Vin <= +6V).
    Rear Panel
    X1, X5 Attenuation
     Approximately 50 Ω at dc.
    FUNCTIONS
    FREQUENCY A
    Range
    DC Coupled
    DC to 125 MHz
    AC Coupled
    10 Hz to 125 MHz
    Minimum Pulse Width
    4 ns at 100 mV, peak-to-peak
    Accuracy
     ± 1 count ± time base error.
    Gate Time (Resolution)
     10 sec to 100 ns (0.1 Hz to 10 MHz) selected in decade steps.
    PERIOD B (Single Shot)
    Repetition Rate
    >=125 MHz
    Minimum Pulse Width
    4 ns at 100 mV, peak-to-peak
    Accuracy
     ± 1 count ± time base error.
    ± 1.4 X CH B trigger error.
    Resolution (Clock Rate)
     10 sec to 100 ns (0.1 Hz to 10 MHz), selected in decade steps.
    PERIOD B (Average)
    Repetition Rate
    >=125 MHz
    Minimum Pulse Width
    4 ns at 100 mV, peak-to-peak
    Clock Rate
     100 ns (10 MHz), fixed.
    Number of Averages (N)
     1 to 10^8, selected in decade steps.
    Resolution
     1 femtosecond (10^-15) to 100 ns, selected in decade steps.
    WIDTH B (Single Shot)
    Minimum Pulse Width
    10 ns.
    Resolution
    (Clock Rate)
     10 sec to 100 ns (0.1 Hz to 10 MHz), selected in decade steps.
    WIDTH B (Average)
    Minimum Pulse Width
    5 ns.
    Repetition Rate
    >=100 MHz
    Minimum Dead Time
     5 ns.
    Clock Rate
     100ns (10 MHz), fixed
    Number of Averages (N)
     1 to 10^8, selected in decade steps.
    Resolution
     100 ns / sqrt(N)
    Time A - B (Single Shot)
    Minimum Time Interval
    12.5 ns.
    Resolution (Clock Rate)
     10sec to 100 ns (0.1 Hz to 10 MHz), selected in decade steps.
    Time A - B (Average)
    Minimum Time Interval
    12.5 ns.
    Minimum Dead Time
     12.5 ns.
    Number of Averages (N)
     1 to 10^8, selected in decade steps.
    Clock Rate
     100 ns (10 MHz) fixed
    Resolution
     100 ns / sqrt(N)
    EVENTS A DURING B (Average)
    Maximum CH A Frequency
    >=125 MHz.
    Minimum CH B Pulse Width
    5 ns
    Minimum Dead Time Between Pulses
     5 ns.
    Number of Averages (N)
     1 to 10^8, selected in decade steps.
    RATIO A/B (Average)
    Frequency Range
    >=12 MHzBoth channels.
    Minimum Pulse Width
    4 ns at 100 mV, peak-to-peakBoth channels.
    Number of Averages (N)
     1 to 10^8, selected in decade steps.
    TOTALIZE A
    Frequency Range
    DC to 125 MHz.Start/Stop function from front panel or rear interface. Overflows with >99,999,999 counts.
    TIME MANUAL
    Clock Rate (Resolution)
     10 sec to 100 ns (0.1 Hz to 10 MHz), selected in decade steps.
    Range
     100 ns to 10^9 sec. Start/Stop function from front panel or rear interface.
    INTERNAL TIME BASES
    Standard Time Base
    Frequency
    10 MHz (100 ns).Adjustable to ± 1 part in 10^7, or better.
    Temperature Stability
     ± 5 ppm.
    Aging
     <= 1 ppm/year
    Option 01 Time Base
    Frequency
    10 MHz (100 ns).Adjustable to ± 2 parts in 10^8, or better
    Temperature Stability
     ± 0.2 ppm of final frequency in less than 10 minutes when cold started at 25° C ambient
    Aging
     < 1 ppm/year.

    above excerpt from DC 503A UNIVERSAL COUNTER Instruction Manual


    OPERATING INSTRUCTIONS

    A brief description of the front panel controls follows.
    Because the Channel A and Channel B controls are identical, only Channel a will be described

    DISPLAY AND UNIT INDICATORS
    DISPLAY READOUTEight-digit, seven segment LED readout with automatically positioned decimal point.
    OVERFLOWWhen illuminated indicates register overflow.
    GATEIndicates the state of the main gate. When lit, the main gate is open (the DC 503A is in the process of making a measurement). When the light is off, the gate is closed.
    GHz/nSECWhen illuminated, indicates the displayed number is gigahertz (GHz) in FREQ A mode or nanoseconds (nSEC) in a time mode.
    MHz/μSECWhen illuminated, indicates the displayed number is Megahertz (MHz) in FREQ A mode or in microseconds (μSEC) in a time mode.
    kHz/mSECWhen illuminated, indicates the displayed number is kilohertz (kHz) in FREQ A mode or milliseconds (mSEC) in a time mode.
    Hz/SECWhen illuminated, indicates the displayed number is Hertz (Hz) in FREQ A mode or seconds (SEC) in a time mode.
    MODE SELECTION AND CONTROL FUNCTIONS
    FUNCTIONSelects the measurement, events, or time counting modes for the counter.

    The TOTALIZE A/TIME MANUAL position is an "either/or" function. TOTALIZE A or TIME MANUAL is selected and set by positioning an internal jumper.
    AVGS/TIMINGDepending on the position of the FUNCTION switch, this switch selects the clock rate which will be counted or the number of measurements to be averaged.
    DISPLAY TIMESets the length of time the reading will be displayed after the count is made and before the next measurement is taken. Display time can be varied from about 0.1 second, fully counterclockwise (ccw), to about 10 seconds fully clockwise(cw). The HOLD position provides continuous display until reset by pushing the RESET button.
    RESETMomentary switch resets the count to zero when operating in the TOTALIZE A mode. Also acts as a master reset, ensuring that the readout has been cleared before the next measurement. Provides a check of all display LED's; when pressed, a row of 8's will be displayed in the readout window.
    START/STOPPush-Push switch acts as a manual gate when the FUNCTION switch is in the TOTALIZE A/TIME MANUAL position. Button in Starts the measurement interval gate; button out terminates the gate.
    CHANNEL A INPUT AND LEVEL FUNCTIONS
    CH A INPUTBNC connector for Channel A signal input. Input impedance is 1 MΩ shunted by approximately 20 pF.
    LEVELSelects the amplitude point on the positive or negative slope of the input signal at which the triggering window is placed.
    SLOPEPush-Push switch selects the slope of the input signal on which triggering will occur. Button out selects plus (+) slope; button in minus (-) slope.
    ATTENPush-Push switch selects X1 (button out) or X5 (button in) attenuation of the input signal.
    COUPLPush-Push switch selects DC (button out) or AC (button in) coupling of the input signal to the attenuator circuit.
    SOURCEPush-Push switch selects the source of the input signal. Button out, EXT, selects the front panel connector as a signal source. Button in, INT, routes the input signal to the counter via the rear interface connections.
    SHAPED OUT AProvides a shaped output signal derived from the output of the Channel A signal shaper circuitry
    SHAPED OUT GNDCommon connector for Channel A shaped output signals.
    TRIG LEVEL APin jack permits monitoring of the Channel A triggering voltage level.

    above excerpt from DC 503A UNIVERSAL COUNTER Instruction Manual

    MISC PART NUMBERS
    Knobs
    1-4366-0494-05Knob : Gray (LEVEL)
    1-3366-1023-07Knob : Gray (DISPLAY TIME)
    Pots/Switches
    1-5 (R500,R600)311-2095-00Res, Var, Nonwir, 10K 10% 12697 (Clarostat 388) (LEVEL)
    1-70 (A14R1410)311-2096-00Res, Var, Nonwir, 1M Ohm 0.5W 12697 )Clarostat 388) (DISPLAY TIME)
    1-70 (A14S1410)Part of A14R1410
    A12S1810263-0074-00Sw, Lever Assy FUNCTION
    A14S1010263-0074-00Sw, Lever Assy TIMING
    A12S1730263-0010-00Switch, PB, 1 Push ATTEN X1/X5
    A12S1731263-0010-00Switch, PB, 1 Push DC/AC
    A12S1732263-0010-00Switch, PB, 1 Push EXT/INT
    A12S1720263-0010-00Switch, PB, 1 Push SLOPE