Pyramid Generator
| PYRAMID GENERATOR USED TO CALIBRATE AND TEST TEKTRONIX AND OTHER HIGH QUALITY OSCILLOSCOPES |
| BRAND NEW -- CALIBRATED -- WARRANTED |
The Pyramid Generator (PG) is a self-contained, portable, battery operated, hand-held device very suitable for laboratory calibrating or field testing
any high-quality digital or analog oscilloscope. It features a crystal-controlled oscillator, a regulated power supply and, in the PERIOD position
of the MODE switch, an amplitude and time duration controlled stairstep output which looks like the vertical cross section of a ten layer Egyptian
Pyramid. The PG features a variable period in selector switch position 1 and eleven calibrated PERIODs going from 50 mS to 20 uS in steps of
1-2-5 sequence in the next eleven positions when the MODE switch is set to the PERIOD position. Each Pyramid stairstep consists of 20 steps total,
10 steps up and 10 steps down in the time frame of one PERIOD cycle. The period signal is available at the PERIOD BNC on the front panel.The
stairstep counts up when the PERIOD level is high and counts down when the PERIOD level is low. The Pyramid output is amplitude-controlled
at 3V peak to peak into 1 M Ohm and 0.3V peak to peak into 50 Ohms.
The PERIOD output is a 6V square wave (Zo=1K) and is used to test the external triggering capabilities of the Unit Under Test (UUT) and can
also be used as a source of a selectable precision signal going from 50mS to 20uS in either a 1-2-4 or 1-2-5 sequence depending on the setting
of the MODE switch.
In the PERIOD position of the MODE switch a 1-2-5 frequency division sequence is used.
In the STEP position of the MODE switch a 1-2-4 frequency division sequence is used.
The PG can be used to reliabily set vertical amplitude calibration, horizontal time calibration and to test triggering capabilities at each of the
ten steps up and the 10 steps down when the MODE switch is in the PERIOD, or 1-2-5 position.
The PG is housed in a light blue powder-coated die-cast aluminum box measuring 4.5" X 3.5" X 1.25" with solid aluminum knobs and bright white
legends on the face. A BNC PERIOD output is provided which is high on the up-count and low on the down-count waveform of the Pyramid.
The PG is powered by a single 9V battery and uses an LED to alert the operator that the battery is getting low and that the generator will soon be out
of calibration if the battery is not replaced. The low battery LED is flashed at power on for about 1 S. Battery life is in excess of 30 hours
at normal room temperatures.
THIS IS A BUY-IT-NOW SALE
$200 FOR THE PYRAMID GENERATOR, $16.75 FOR USPS PRIORITY SHIPPING (ONLY IN CONUS)
Mr. Martin L., an earlier purchaser of a PG, has been kind enough to prepare a YouTube demonstration of the PG in action.
The YouTube demonstration can be accessed by clicking here to view the video
(note the two underscores between the Y and 8, these underscores may be masked by the underline if it is present).Another earlier purchaser, Mr. Bruce P., of Oxford Michigan has also been kind enough to prepare a YouTube demonstration of the PG in action.
The YouTube demonstration can be accessed by clicking here to view the video.
Both presenters cover the operation of the PG using calibrated analog and digital oscilloscopes in a most complete and professional
manner.
| HISTORY BEHIND THE PYRAMID GENERATOR |
I once attended the bi-monthly electronics swap meet in Santa Ana, CA. There was an out-of-state vendor there who had a number of Tektronix
475A and 485 oscilloscopes that were very reasonably priced. The vendor assured me that all of these oscilloscopes were in working
order; however, there was no power available to verify this statement. I accepted this explanation and after several minutes of
intense haggling we arrived at a mutually agreeable price and then I was the proud owner of four 485 and three 475A Tektronix
oscilloscopes. During the next week I fired them up and found that only two of the 475A's and none of the 485's had a trace visible
on them. One of the 485's was lacking the inverter board and as well had no tunnel diodes nor any of the socketed ICs. Needless
to say, I was not a happy shopper. And to top it all off, I did not get the seller's contact information. I decided that I needed
a portable calibration tester or a very long extension cord. I do not design extension cords but I do design portable testers-the
Pyramid Generator is the culmination of that effort.
In the PERIOD position of the MODE switch there are eleven Pyramid crystal-controlled PERIODs, 50mS, 20mS, 10 mS, 5mS, 2mS, 1mS, 500uS,200uS, 100uS, 50uS and 20uS.In the STEP position of the MODE switch there are eleven Pyramid crystal-controlled STEPs, 2mS/DIV, 1mS/DIV, 500uS/DIV, 200uS/DIV,100uS/DIV, 50uS/DIV, 20uS/DIV, 10uS/DIV, 5uS/DIV, 2uS/DIV, 1uS/DIV.One potentiometer-controlled switch setting with variable periods from 100mS to 5mS.Low battery warning LED on front panel. Flashed upon "power-on",PYRAMID OUTPUT BNC waveform is 3V P-P into 1 MO and 0.3V P-P into 50 Ohms. Accuracy is +/- 2% into 50 Ohms.Crystal-controlled PERIOD and STEP accuracy is +/-50 PPM (Parts Per Million) or +/- .005%Regulated power supply used to stabilize output amplitude.PERIOD BNC output provided to allow external triggering checks. Waveform is high on up count, low on down count.Single 9 Volt alkaline battery powers the PG.Battery life, under highest frequency output and fresh battery, is in excess of 30 hours.Housed in die-cast aluminum case with light blue powder-coated exterior, bright white legends and solid aluminum knobs.Rubber bumpers for feet.Warranteed for six months after purchase if no signs of abusive force or a corroded battery are present.Please write me at reed714@sbcglobal.net for any additional information you may desire.USPS Priority shipping to any point in the CONUS. Please click here for overseas shipping information during the sale.
Each PG comes with a free extensive manual which covers the usage, care, calibration and feeding of the device. If you would like a copy of
this manual for your self then click here to get your free .pdf copy.
You will not be besieged by endless e-mails professing the merits of the PG. You will get one note from me and that will be the
attached manual.
The MODE switch is incorporated because the 2 to 5 transition on the UUT is not divisible by 2, it is divisible by a factor of 2.5. The
internal electronics is modified using the MODE switch to overcome this problem. For instance, you are in switch position 4 viewing
a 10 mS Pyramid PERIOD with the UUT in 1mS/DIV and the MODE switch in the STEP position. When you advance to position 5, the 5mS
Pyramid PERIOD, and advance the TIME/DIV control on the UUT to 500uS/DIV you will see that the Pyramid Period is 4mS. Operating
the MODE switch to the PERIOD position will bring the period to the full 5mS.If you want to view the Pyramid Period switch the MODE switch to PERIOD, the frequency division ratio will be 1-2-5.
If you want to view the individial Pyramid steps, switch the MODE switch to STEP, the frequency division ratio will be 1-2-4.
The display shows two pictures of the output of the PG. The one with the full 20 steps also has the PERIOD waveform shown on the
lower portion of the picture and the TIME/DIV setting on the oscilloscope is set at 100uS/DIV. The oscilloscope is being
triggered on the PERIOD input. You will note that the PERIOD waveform is high when the STEP count is going up and the
PERIOD waveform is low while the STEP count is going down. There are 20 steps total, 10 up steps and 10 down steps, each
step is 50uS so 20 steps would be 1000uS or 1mS. This is correct as the horizontal time is 100uS/DIV times 10 DIV for a
total of 1000uS or 1mS.The single waveform picture shows 10 steps up at 50uS/DIV. The PG is set to position 7 (50uS/DIV) and the MODE switch is in the STEP
position. The 50uS/DIV steps show clearly the accurate step transition at each vertical graticule line. This setting is the
best one to use while calibrating the horizontal timebase on an oscilloscope.
The front panel of the PG portrays the relationship between the STEP and Period waveforms.
Dotted lines are used to illustrate the relationship between the PERIOD and STEP waveforms.
When the MODE switch is in the up or STEP position the STEP signal is available at the upper BNC and the upper labels on
the rotary selector switch are applicable.
When the MODE switch is in the down or PERIOD position the lower BNC has the PERIOD signal and the lower labels on each position of
the selector switch are applicable.
The STEP and PERIOD signals are always available irrespective of the position of the MODE switch. It is just that the 1-2-4 or
the 1-2-5 division is not a problem when the operator is aware of the signal desired and the position of the MODE switch.
The PG has a 10 step up and 10 step down PYRAMID OUTPUT waveform measuring 3 Volts peak-to-peak into 1 M Ohm and 0.3 Volts peak-to-peak
into 50 Ohms. Each step on the Pyramid will be approximately 30 mV. The step-to-step amplitude change is not controlled and is
not linear. When the UUT input is terminated into 50 Ohms the peak-to-peak Pyramid step will be 300 mV. The output impedance of
the PYRAMID OUTPUT signal is 450 Ohms, +/- 1%.
The STEP duration and the Pyramid PERIOD table is as follows:
Pyramid Generator Outputs Versus Switch Position| Selector Switch Position | MODE Switch In PERIOD Position. Each STEP duration is: | MODE Switch In PERIOD Position. Each PERIOD duration is: |
|---|
| 1 | Variable | Variable |
| 2 | 2mS/DIV | 50mS |
| 3 | 1mS/DIV | 20mS |
| 4 | 500uS/DIV | 10mS |
| 5 | 200uS/DIV | 5mS |
| 6 | 100uS/DIV | 2mS |
| 7 | 50uS/DIV | 1mS |
| 8 | 20uS/DIV | 500uS |
| 9 | 10uS/DIV | 200uS |
| 10 | 5uS/DIV | 100uS |
| 11 | 2uS/DIV | 50uS |
| 12 | 1uS/DIV | 20uS |
The PERIOD signal is also available as a precision time controlled standard. The PERIOD signal has a 1K series resistor in the output to
protect the integrity of the internal electronics. This 1K resistor may be used as a dropping device when a Zener diode of a required
value is connected to ground to clip the signal at the voltage value of the Zener diode.
PERIOD Outputs Versus Switch Position| Selector Switch Position | MODE Switch In STEP Position. Each 1-2-4 PERIOD duration is: | MODE Switch In PERIOD Position. Each 1-2-5 PERIOD duration is: |
|---|
| 1 | Variable | Variable |
| 2 | 40mS/DIV | 50mS |
| 3 | 20mS/DIV | 20mS |
| 4 | 10mS/DIV | 10mS |
| 5 | 4mS/DIV | 5mS |
| 6 | 2mS/DIV | 2mS |
| 7 | 1mS/DIV | 1mS |
| 8 | 400uS/DIV | 500uS |
| 9 | 200uS/DIV | 200uS |
| 10 | 100uS/DIV | 100uS |
| 11 | 40uS/DIV | 50uS |
| 12 | 20uS/DIV | 20uS |
The PG can be used to test the UUT's ability to trigger on each step of the Pyramid waveform by slowly advancing the UUT trigger level and changing the
UUT trigger slope from + to -. The UUT should be able to trigger on the start of the Pyramid steps and progressively trigger on higher and higher
levels as the Triggering Level control is rotated.
| THREE TEST SETUPS USING THE PG |
I will detail three test setups and describe what you can learn from each setup.
1) TRIGGERING
Connect the STEP OUTPUT to the vertical input on the UUT. Trigger the UUT internally and obtain a stable display. Slowly rotate the
UUT TRIG LEVEL control CW and CCW. Change the UUT TRIGgering SLOPE from positive to negative and watch the display as you rotate the
TRIG LEVEL. If the triggering is working properly you should be able to see the UUT trigger on successively higher or lower levels
of the PG waveform as the TRIG LEVEL and SLOPE controls are rotated.
2) VERTICAL AMPLITUDE
Connect the STEP OUTPUT to the vertical input of the UUT, connect the PERIOD output to the EXTernal TRIGger input on the UUT.
Obtain a stable signal with one full cycle of 20 stair steps. Adjust the VERT POSition control so the very bottom of the PG
waveform is on a lower graticule line. Adjust the UUT internal vertical gain control to obtain exactly 3 Volts peak-to-peak
waveform on the UUT screen. You have now calibrated the vertical deflection on the UUT.
3) HORIZONTAL LINEARITY
Obtain a stable display as in 2) above. Again, trigger on the PG PERIOD output. Operate the PG's MODE switch to STEP. Rotate the UUT
V/DIV control to see 10 steps from the PG on the UUT. Adjust the internal horizontal gain potentiometer inside the UUT to obtain a
step at each vertical graticule mark. You have now calibrated the horizontal sweep on the UUT. It is a good idea to check each
setting of the TIME/DIV switch on the UUT against the output of the PG. Doing this will confirm that the precision resistors and
capacitors forming the UUT time constants are within tolerance.
Please click here to get or clarify information on the PG test setups..
| FREQUENCY LIMITATIONS OF THE OUTPUT WAVEFORM |
The D2A (Digital 2 Analog) converter portion of the PYRAMID OUTPUT uses a counter. When the input frequency is high, noticable switching
spikes and rounding of the STEP corners is apparent when the output load is 1 M Ohm. The device is perfectly usable at this level,
it is just not too pretty. For that reason I have down graded the amplitude fidelity at the higher frequencies when the load is 1 M Ohm.
To see a cleaner waveform terminate the oscilloscope's input in 50 Ohms.
The PG carries an unlimited 6-month warranty after receipt by the original buyer provided that there is no indication of mistreatmentof the unit.
This includes damage to the case or hardware, corroded battery contacts or other evidence of mistreatment. Buyer is responsible for all shipping costs.
The PG carries a no-questions-asked 5-day-after-receipt return policy providing the buyer agrees to pay all expenses. A PayPal transfer
or refund check, minus shipping, PayPal and eBay fees, will be issued within five days to the original purchaser only. Considerations
can be made to allow for extended shipping times or customs delays.
The successiful bidder agrees to pay USPS Priority Shipping which is $16.75 for under 2 pound shipments in the CONUS. I would be happy
to ship Fedex or UPS, buyers choice. Extra fees may apply. If you are not in the CONUS please click here to send a note requesting
information on overseas PG shipping. I will also ship on your account or, you can snail mail me a prepaid shipping label. Do
not e-mail me a prepaid shipping label as it cannot be reliabily scanned at the carrier's station. Shipping on your account can
only be to your registered location, not a secondary location. Overseas shipping may carry additional shipping fees. I use
USPS Priority International for all non-CONUS shipments. The tracking number will be sent to the purchaser after shipping.
Insurance is mandatory for all international shipments and optional, but recommended, for CONUS shipments. Insurance fees
are in addition to the purchase price and must be negotated after the purchase date but before shipping. Please include insurance
fees and a note to me requesting insurance when paying.
All financial transactions must be made through PayPal. Cash is accepted but only for local pickup on a face-to-face basis. No additional charges for local pickup.
Seller reserves the right to reject bids from private, hidden, annoying or negative feedback bidders.
I take my eBay feedback rating very seriously! I would appreciate your courtesy of contacting me by clicking here should there be a
problem with any item purchased. I will make every attempt to resolve the issue as soon as possible to the buyers satisfaction
or your money will be cheerfully refunded. I always leave positive feedback for buyers when their payment is received. Your
feedback, once the transaction is completed, would be greatly appreciated. Buy with confidence from a seller that stands firmly
behind every item that is sold.
Remember, your bid is your word, please bid responsibly.
| PYRAMID GENERATOR SPECIFICATIONS |
| UUT 50 Ohms Input Impedance | UUT 1 MO Input Impedance |
|---|
| Output Amplitude | 0.3V Peak-to-peak | 3V Peak-to-peak |
| Rise Time | 30nS | 200nS |
| Fall Time | 50nS | 200nS |
| Accuracy | +/- 2% | +/- 3% on Selector Switch ranges 1 to 9. +/-5% on Selector Switch ranges above 9. |
| Selector Switch Position | STEP output with MODE Switch in PERIOD position | PERIOD output with MODE Switch in PERIOD position |
|---|
| 1 | Variable, potentiometer controlled | Variable, potentiometer controlled |
| 2 | 2mS/DIV | 50mS |
| 3 | 1mS/DIV | 20mS |
| 4 | 500uS/DIV | 10mS |
| 5 | 200uS/DIV | 5mS |
| 6 | 100uS/DIV | 2mS |
| 7 | 50uS/DIV | 1mS |
| 8 | 20uS/DIV | 500uS |
| 9 | 10uS/DIV | 200uS |
| 10 | 5uS/DIV | 100uS |
| 11 | 2uS/DIV | 50uS |
| 12 | 1uS/DIV | 20uS |
| Accuracy | +/- 50 PPM on all ranges | +/- 50 PPM on all ranges |
| CONTROL | FUNCTION |
|---|
| BATTERY | Connects the battery to the electronics. No standby current is drawn in the 0 position. |
| LED | Warns the operator that the battery voltage is falling below 8V and that the unit will soon be out of calibration. LED flashes for 1 S upon power on. |
| MODE | Used to modify the internal electronics such that the 1-2-5 sequence is maintained in the PERIOD position and a 1-2-4 sequence in the STEP position in both the STEP and PERIOD position of the MODE switch. |
| PERIOD Output BNC | A 6 Volt square wave used to test the external triggering capabilities of the UUT. Output is high on the count up portion of the Pyramid waveform and low on the down count portion. Rise and fall times are about 100nS. Zo=1K. |
| STEP Waveform Output BNC | The Pyramid waveform output BNC |
| Selector Switch | A twelve position switch used to select the output waveform frequency. |
| Variable fRequency potentiometer | Used only in position 1 of the selector switch to vary the output waveform PERIOD. |
| PROPERTY | SPECIFICATION |
|---|
| Housing | The Pyramid Generator is housed in a Hammond 1590BB die-cast aluminum enclosure measuring 4.5" X 3.5" X 1.25". A die-cast bottom lid is held in place with four Phillips head screws. |
| Finish | The Pyramid Generator case and base plate are powder coated a light blue non-metallic finish with bright white legends on the front panel. Bright finish matching solid aluminum knobs are used on the front panel. |
| Feet | Four stick-on feet are provided |
| Battery | The Pyramid Generator uses one standard alkaline 9 Volt battery held in place by a sturdy metal clip. Battery replacement requires removal of four Phillips flat head screws on the bottom lid. No standby current is drawn when the BATTERY switch is in the 0 position. |
| Weight | The Pyramid Generator weighs under 1 pound with battery installed. |
| Shipping | The Pyramid Generator is shipped via USPS Priority Mail unless instructed otherwise. International shipping uses Priority International or the buyers choice. |
Congratulations, you made it to THE END
|