| DC to 100 MHz |
| .01Hz resolution with Phase Locked Loop |
| Measures Pulse Widths |
| Period Averaging |
| 6 Digits |
|  |
|
There are no options for the DC 504A
The Tektronix DC 504A is a multi-function counter/timer designed to operate in one compartment of any
TM 500 or TM 5000-Series power module.
Frequency measurements to 100 MHz are within the capability of the DC 504A. Frequencies above 10 MHz are internally
prescaled. Measurement of pulse widths and periods at rates up to 2.5 MHz is possible. Width and Period averaging of
up to 100 events is possible, An autorange feature allows the counter to automatically select the gate time (up to one
second) or number of averages (up to 100). A x100 phase-locked loop multiplier automatically increases display
resolution by a factor of 100 in the 10 Hz to 25 kHz frequency range. The 10 MHz internal time base provides a
single-shot resolution of 100 ns. Input signals can be ac or dc coupled and attenuated by a factor of five. All
measurement results are displayed in a six digit LED readout.
ELECTRICAL CHARACTERISTICS
| Characteristics | Performance Requirements | Supplemental Information |
| INPUTS |
|---|
| Input Frequency Range |
| Front Panel | Dc coupled, 0 to 100 MHz
Ac coupled, 10 Hz to 100 MHz | |
| Rear Interface | Dc coupled, 0 to 50 MHz
Ac coupled, 10 Hz to 50 MHz | |
| Input Sensitivity |
| x 1 Attenuation | 30 mV rms sinewave (85 mV p-p) to 100 MHz
85 mV p-p pulse at a minimum width of 5 ns |
| x 5 Attenuation Accuracy | | Within 2% at dc |
| Input Dynamic Range |
| X1 | | 2.0 V p-p signal within a ± 2.0 Vdc window |
| X5 | | 10.0 V p-p signal within a ± 10.0 Vdc window |
| Trigger Level Range | | Typically greater than ± 2V X attenuator setting. |
| Maximum Safe Input Voltage |
| Front Panel |
| X1 | | 200 V pk; 400 V p-p from dc to 50 kHz, derate to 15 V p-p from 1.33 MHz to 100 MHz |
| X5 | | 200 V pk; 400 V p-p from dc to 5 MHz, derate to 20 V p-p at 100 MHz |
| Rear Interface | | <= 4 V pk |
| Input Impedance |
Front Panel
x1, x5 | | 1 MΩ, paralleled by approximately 25 pF |
Rear Interface
x1, x5 | | 50 ohms ± 10 % at dc |
| FUNCTIONS |
|---|
| Frequency to 10 MHz |
| Range | Dc coupled, 0 Hz to 10 MHz
Ac coupled, 10 Hz to 10 MHz |
| Accuracy | | ± 1 count ± time base error x freq |
| Gate Time | | 10 ms to 10 sec, selectable in decade steps, or autoranging (10 ms to 1 sec only) |
| Resolution |
| Non-phase-locked | | 100 Hz to 0.1 Hz, selectable in decade steps, or
autoranging (100 Hz to 1 Hz only) |
| Phase Locked | | 1 Hz to 0.001 Hz, selectable in decade steps, or autoranging (1 Hz to 0.01 Hz only) |
| Lock Range | 10 Hz <= Freq <= 25 kHz |
| Multiplication | x 100 |
| Lock Time | <= 5 seconds | Phase Lock Loop automatically increases resolution whenever loop locks. PLL defeat can be accomplished by an internal jumper. |
| Frequency to 100 MHz |
| Range | Dc coupled, 0 Hz to 100 MHz
Ac coupled, 10 Hz to 100 MHz |
| Prescale Factor | ÷ 10 |
| Accuracy | | ± 1 count ± time base error x freq |
| Gate Time (Resolution) | | 10 ms to 10 sec (1 kHz to 1 Hx). Selectable in decade steps, or autoranging (10 ms to 1 sec only). |
| | Period AVG |
| Freq Range | Dc coupled, 0 Hz to 2.5 HMz
Ac coupled, 10 Hz to 2.5 MHz | Overflows above 9999.9 μs (100 ms) |
| Number of Averages (N) | | 1 to 1000, selectable in decade steps, or autoranging (1 to 100 only). |
| Resolution | | 100 ns to 100 ps, selectable in decade steps or autoranging (100 ns to 1 ns only). |
| Accuracy | | ± (100 ns/N) ± time base error x period
± 1.4 x (trigger jitter error / N) |
| Totalize |
| Freq Range | Dc coupled, 0 Hz to 10 MHz
Ac coupled, 10 Hz to 10 MHz | Overflows above
999999. Display update run/hold will hold display while counter continues to advance. Releasing run/hold will update display to new value. |
| TIME BASE |
|---|
| Time Base |
| Frequency (at calibration) | 10 MHz ± 1 x 10(-7) |
| Adjustment Resolution | ± 5 x 10(-8) |
Temperature Stability
(0°C to +50°C) | ± 5 x 10(-6) (±5ppm) |
| Aging | <= 1 ppm/year |
above excerpt from DC 504A COUNTER / TIMER Instruction Manual
CONTROLS AND CONNECTORS
Following is a brief description of the front panel controls and connectors.
| READOUT DISPLAY | Six digit LED readout with automatically positioned decimal point and leading zero suppression. Display reads in KILOHERTZ or MICROSECONDS. |
| GATE | Indicates the status of the main gate. When illuminated, the gate is open; the instrument is in the process of making a measurement. When extinguished, the gate is closed. |
| OVERFLOW | When illuminated, indicates register overflow. |
| MULTIPLIER LOCK | Illuminated when the Multiplier (Phase Lock Loop) circuit is active. The Multiplier is automatically activated when measuring frequencies between 10 Hz and 25 kHz. This circuit multiplies the measured frequency by 100, providing two additional digits of display resolution. |
| FUNCTION | Selects the following measurement or counting modes for the instrument. |
| FREQ TO 10 MHz | Measures directly and displays the frequency of input signals up to 10 MHz. |
| FREQ TO 100 MHz | Internally prescales and displays the frequency of input signals up to 100 MHz. |
| PERIOD | Measures and displays the period of the input signal. |
| WIDTH (up) | Measures and displays the time interval between the triggering point on the positive leading edge to the corresponding point on the trailing edge of a pulse applied to the input. |
| WIDTH (down) | Measures and displays the time interval between the triggering point on the negative leading edge to the corresponding point on the trailing edge of a pulse applied to the input. |
| TOTALIZE | Pulses applied to the input will be displayed in a running total until the counter is manually reset or register overflow occurs. |
| TIME/AVGS | Depending on the position of the FUNCTION switch, selects the gate time or the number of measurements to be averaged. In AUTO, a gate time that will display six digits is automatically selected. |
| RESET | Resets the count to zero when operating in the TOTALIZE mode. Acts as a master reset ensuring that the readout has been cleared before the next measurement. Also provides a check of all display LED's; when prssed and held, a row of 8's is displayed. |
| DISPLAY UPDATE | When the button is in the RUN (out) position, the DC 504A counts or makes measurements continuously.
When the button is in the HOLD (in) position and the instrument is in a measurement mode, the last measurement is displayed and no more made until the button is released.
When the instrument is counting (TOTALIZE), moving the button to the HOLD position stops the display only; the count continues to accumulate in the registers. When the button is released, the display is automatically updated to the current count accumulation and continues to run. |
| TRIGGER LEVEL | Selects the amplitude point on the positive or negative slope of the input signal at which the triggering window is placed. |
| ATTEN | Selects the attenuation factor for the input signal. When the button is in the x1 (out) position the input signal is not attenuated. The input signal is attenuated by a factor of five when the button is in the x5 (in) position. |
| COUPL | Selects the method of coupling the input signal to the counter. When the button is in the DC (out) position, the signal is applied directly. The input signal is capacitively coupled to the input when the button is in the AC (in) position. |
above excerpt from DC 504A COUNTER / TIMER Instruction Manual
| Knobs |
| 1-4 | 366-1023-13 | Knob, Gray (inner-TIME/AVG) |
| 1-5 | 366-2156-00 | Large Knob, Dove Gray (outer-FUNCTION) |
| 1-15 | 366-0494-08 | Knob, Grey, New Gen - TRIGGER LEVEL |
| Pots/Switches |
| 1-28 A10R4037 | 311-2188-00 | Res, Var, Non@@, 1K, 20%, 0.5W (A-B WP4G056S102MZ) TRIGGER LEVEL |
| 1-39 A12S2061 | 260-2123-00 | Switch, Rotary, Dual Concentric (Stackpole 73-8501) FUNCTION, TIME |
|
