PHILIPS PM3377 (01) PDF Document

The PHILIPS PM3377 Digital Storage Oscilloscope (DSO) range has the following easy-to-use features:

• 60 MHz analog oscilloscope for PM3350A and PM3355 models.

• 100 MHz analog oscilloscope for PM3365A and PM3375 models.

• 100 Msamples/s single shot digital acquisition on both channels for PM3350A and PM3365A models.

• 250 Msamples/s single shot digital acquisition on both channels for PM3355 and PM3375 models.

• Auto Set for instant signal viewing in both analog and digital oscilloscope modes.

• Cursors for time and amplitude measurements in digital oscilloscope mode.

• Reference memories and non-volatile storage of all waveforms.

• Optional interface facilities for remote control and hard copy output.

• Storage of 64 front settings.

Whenever it is likely that safety protection has been impaired, the PHILIPS PM3377 must be made inoperative and be secured against any unintended operation. The matter should then be referred to qualified technicians. Safety protection is likely to be impaired if, for example, the instrument fails to perform the intended measurements or shows visible damage.

To get started with the PHILIPS PM3377, follow these steps:

1. Connect the oscilloscope to the mains (line) voltage.

2. Switch the oscilloscope on by means of the push-button POWER LINE ON.

3. Adjust the TRACE ROTATION by means of a screwdriver so that the trace is parallel with the horizontal graticule lines.

4. Connect a probe to input A of the oscilloscope.

5. Connect the other end of the probe to the CAL output of the oscilloscope.

6. Press the AUTO SET key.

The AUTO SET function will automatically set all relevant parameters of the oscilloscope (attenuator setting, time base setting and trigger source setting) for an optimum trace.

If the probe you use is an attenuator probe (10:1 or 100:1), it may be necessary to adjust it for the correct compensation, according to the instructions in the probe manual.

The PHILIPS PM3377 is provided with a built-in memory back-up circuit, if batteries are fitted. Note that batteries are not factory installed and must be fitted at delivery. The memory back-up batteries (2xLR6 Alkaline Penlight) placement and replacement must be carried out only by a qualified technician.

To replace the batteries:

1. The instrument must be disconnected from the mains (line).

2. Remove the screw that holds the top cover at the rear of the instrument.

3. Gently push the cover backwards until it can be lifted.

4. Remove the cover by lifting it clear of the instrument. The memory battery back-up unit is now accessible. This unit is located on the instrument’s rear panel.

5. Ease off the clip that holds the memory back up unit to the chassis.

6. Gently slide the battery holder out of the chassis.

7. Install both batteries in their holders. The installation direction of the batteries is shown on the battery holder.

NOTE: When replacing the memory back-up unit, take care not to damage the wiring in the vicinity of the battery holder.

By pulling both handle ends outwards away from the instrument, the handle on your PHILIPS PM3377 can be rotated to allow the following instrument positions:

• vertically on its rear feet;

• horizontally on its bottom feet;

• in two sloping positions on the handle.

ATTENTION: Do not position the oscilloscope on any surface which radiates heat, or in direct sunlight. Ensure that the ventilation holes at the rear and top are free from obstruction.

After switching on the PHILIPS PM3377 with the POWER LINE ON push button, the screen controls can be adjusted for optimum illumination, trace and spot quality.

• The trace and text intensity is set by the INTENS rotary knob, and a sharp display is obtained by the FOCUS rotary knob.

• The screw driver control TRACE ROTATION is used to set a grounded trace parallel with the horizontal graticule lines.

• The graticule of the screen can be lit-up by the ILLUMINATION rotary knob, which can be used in dark environments or for making photographs.

A flashing segment on the Liquid Crystal Display (LCD) of your PHILIPS PM3377 indicates a situation that requires your special attention. Examples include:

• an incorrect selection of knobs/keys controls.

• a VAR rotary knob is in an uncalibrated position.

• the end of a UP-DOWN control range.

• a key has been operated during the PLOT action.

• the DISPL PART UP-DOWN key has been pressed in TB MAGN x1 mode.

• display of register only.

The UP-DOWN keys on the PHILIPS PM3377 select the required setting out of the range of settings possible for that function. They are used for the attenuator setting, the time base setting, the trigger delay setting and the display part setting.

The rotary knobs on the PHILIPS PM3377 allow for continuously-variable adjustment of certain functions:

• Y POS (A): Adjusts the vertical screen position for channel A.

• VAR A: Adjusts the variable attenuation for channel A. It is in the CALibrated position when fully clockwise.

• Y POS (B): Adjusts the vertical screen position for channel B.

• VAR B: Adjusts the variable attenuation for channel B. It is in the CALibrated position when fully clockwise.

• X POS: Adjusts the horizontal screen position for the time-base.

• VAR (X): Adjusts the variable time-base (not in DIGITAL MEMORY mode). It is in the CALibrated position when fully clockwise.

• TRIG LEVEL: Adjusts the trigger level.

• HOLD OFF: Adjusts the hold off time. It is in the normal position (minimum HOLD OFF) when fully clockwise.

First, ensure the oscilloscope is operating in analog mode by checking that the DIGITAL MEMORY indication in the LCD is off. If it is on, press the DIGITAL MEMORY key to switch to analog mode. By pressing the AUTO SET key, the oscilloscope will automatically set the main functions to a clear optimal setting. Further adjustments and selections can then be made by operating the various keys and knobs for three main functions: Vertical mode, Horizontal mode, and Trigger mode.

In analog vertical mode on the PHILIPS PM3377, you can make the following adjustments:

• Vertical display mode selection: Press the A/B key to select the channel you want to see (A, B, or both simultaneously). If ADD is in use, you can switch off channels A and B.

• Adjustment of the absolute zero level: Press the GND key to interrupt the input signal and ground the signal path. Use the Y POS rotary knob to position the zero level anywhere on the screen. This is necessary for all DC measurements. Pressing the GND key again reconnects the signal to the input.

• Channel coupling: Press the AC/DC key to select the coupling. In AC position, the DC component of the signal is rejected. In DC position, the full bandwidth is available. AC coupling is used when a small AC signal must be measured on a large DC voltage.

• Vertical amplitude adjustment: Operate the V…mV UP-DOWN key for the desired channel to select a setting from 2 mV to 10 V per division in a fixed 1-2-5 sequence.

• Vertical variable attenuation: Adjust the VAR rotary knob to change the attenuation. The UNCAL position is used when a measurement is taken in percentages. The LCD will flash “>” to indicate it is uncalibrated. For example, for rise-time measurements, you can set the peak-to-peak value of a waveform to 5 divisions (100%) and then easily read the time between the 10% and 90% levels from the screen.

• Selection of ALTERNATED or CHOPPED display: When displaying two signals, press the ALT/CHOP key. In ALT mode, the CRT beam alternately traces one signal sweep and then the other. This is mainly used for high-speed time-base settings (from around 0.1 ms/div and above). In CHOP mode, the beam chops from one signal to the other at a fast switching frequency, suitable for low-speed signals.

• Selection of ADD, NORMAL or INVERTED display: Press the ADD/INVERT key. “INVERT” is active on channel B. In ADD mode, channel B is added to channel A (A+B). In ADD INVERT mode, channel B is subtracted from channel A (A-B). The differential mode (A-B) is useful for rejecting common-mode signals, such as hum.

In analog horizontal mode on the PHILIPS PM3377, you can make the following selections:

• Selection of X deflection or horizontal time-base: Press the X DEFL key. In X deflection mode, the oscilloscope shows one signal displayed as a function of another (X-Y graph). The required X-axis signal is selected by the TRIG OR X SOURCE key (A, B, EXT, or LINE). In horizontal time-base mode, the display shows the measured signal vs time (Y-t graph).

• Selection of horizontal time scale: Use the TB s…µs UP-DOWN key to select the time-base speed in a 1-2-5 sequence. Use the VAR rotary knob to make fine adjustments between the 1-2-5 steps. Use the X MAGN key to expand the time-base 10 times. Operate the X POS rotary knob to shift the trace horizontally across the screen.

In analog mode on the PHILIPS PM3377, you can configure the following trigger settings:

• Time-base trigger mode: Press the TB TRIG MODE key to select one of three modes.
– AUTO: The horizontal sweep normally starts when a trigger occurs. If no trigger is detected within 100 ms after the last sweep, a sweep start is automatically generated. This means a trace is always visible on the display.
– TRIG: The horizontal sweep will only start on a trigger pulse derived from the selected trigger source.
– SINGLE: The horizontal sweep runs only once after it is armed by the RESET key and a trigger pulse is received. This mode is very useful to capture single events.

• Trigger source selection: Press the TRIG OR X SOURCE key to select from:
– A: channel A
– A B: composite channel A and channel B (alternates between A and B, only possible in alternated display mode)
– B: channel B
– EXT: channel EXTERNAL
– LINE: 50 Hz or 60 Hz sine-wave derived from the line voltage.

• Trigger level: Adjust the TRIG LEVEL rotary knob to set the point on the signal waveform where the time-base sweep is triggered.

• Trigger coupling: Press the TRIG COUPL key to select one of six modes:
– P-P: Peak-to-peak triggering gives automatic ranging of the TRIG LEVEL knob, with the range determined by the peak-to-peak value of the signal. DC signals are rejected.
– DC: The full bandwidth of the trigger channel is available, while the level range of the rotary knob is more than +/- 8 divisions.
– TVF: TV frame triggering allows triggering at the slow TV frame (field) synchronisation pulses.
– TVL: TV line triggering allows triggering at the fast TV line synchronisation pulses.
– LF: The signal used for triggering is first passed through a low-pass filter with a cut-off frequency of 50 kHz. All components with high frequencies are rejected.
– HF: The signal used for triggering is first passed through a high-pass filter with a cut-off frequency of 50 kHz. All components with low frequencies are rejected.

• Trigger slope selection: Press the slope key to select triggering on a positive-going slope or a negative-going slope.

• Hold-off time: Use the HOLD OFF rotary knob to prevent “false” triggering and “double writing” when examining multiple pulse signals. It inhibits the trigger circuit for a period of time set by the knob. Adjusting the hold-off time will inhibit the trigger unit until it sees the first pulse again, so it gives a stable display.

To use the PHILIPS PM3377 as a digital storage oscilloscope, first ensure it is in digital mode. The DIGITAL MEMORY indication in the LCD will be on. If it is not, press the DIGITAL MEMORY key. By pressing the AUTO SET key, the oscilloscope will automatically set the main functions for the most convenient setting.

Further adjustments can be made by operating the keys. In DIGITAL MEMORY mode, there are more functions available than in analog mode. The analog functions that are NOT available in digital mode are: ADD, ALT/CHOP, COMP TRIG, X VAR.

In this section, only the digital functions are described.

The PHILIPS PM3377 has two types of memory in digital mode: a display memory (R0) and three register memories (R1, R2, R3) for storing reference waveforms. Waveforms stored in registers are retained after power down if a battery back-up is equipped.

• Loading of register memory: To store a waveform in a register, first select a destination register R1, R2, or R3 using the softkeys MEMORY and then REGISTERS. When one of these is chosen, you only have to press the LOAD key to store the signal into the register.

• Display of register memory: Pressing the DISPLay key once will show the contents of the display memory and the selected register memory (R1, R2 or R3) together on the screen. Pressing the DISPLay key a second time will show only the contents of the selected register memory. Pressing it a third time will result in displaying the contents of the display memory again.

• Status of register memory: Pressing the STATUS key once and keeping it pressed enables the LCD to show the full settings of the selected register memory (R1 or R2 or R3). Pressing the STATUS key twice within one second and keeping it pressed, the LCD will show the complete settings of the display memory (R0).

In digital horizontal mode on the PHILIPS PM3377, you can select the time scale using the TB s…µs UP-DOWN key. The digital time-base has three modes, and the adjacent figure shows the time-base ranges in relation to the sample rate and resolution. Only in SAMPLING mode are repetitive signals needed.

• ROLL (50 s/div … 1 s/div): In ROLL mode the screen build-up is from right to left. This is used for lower frequency signals. The build-up is point-by-point at the right-hand side of the screen and moves to the left. The ROLL mode is operative until the release of the RESET knob, or when changing the triggering or amplitude control.

• RECURRENT (0.5 s/div … 0.5 µs/div or 0.2 µs/div): In RECURRENT mode the screen build-up is from left to right. Signals with intermediate frequencies can be made visible. The signal is sampled at fixed time intervals, the length of which depends on the time-base setting.

• SAMPLING (0.2 µs/div … 20 ns/div or 0.1 µs/div … 20 ns/div): In SAMPLING mode, repetitive signals are needed for a screen build-up from left to right. Higher frequency signals can be captured up to the full bandwidth of the oscilloscope. With sequential sampling, one point along the waveform is sampled per sweep until enough points are acquired.

You can use the X MAGN key for horizontal magnification of 2, 4, 8, 16, or 32 times. The DISPL PART UP-DOWN key allows you to select which part of interest in a magnified signal is displayed.

The TRIGGER DELAY setting on the PHILIPS PM3377, adjusted by the TRIG DEL UP-DOWN key, offers PRE- and POST triggering in digital mode.

• PRE-triggering: This allows you to look BEFORE the trigger point. For example, if the trigger delay is set to -10 divisions, the trigger point is at the far RIGHT vertical graticule line. What you see is the signal BEFORE the trigger point. This mode is useful for observing events leading up to a problem, such as a mains (line) transient. The maximum PRE-triggering is 10 divisions.

• In trigger delay = 0 divisions: The trigger point is at the LEFT vertical graticule line.

• POST-triggering: This allows you to look AFTER the trigger point. For example, if the trigger delay is set to +10 divisions, the trigger point is one full screen LEFT of the screen that you see. This mode effectively stretches the memory capacity and is useful when measuring a certain line in a TV pattern. The maximum POST-triggering depends on the model, ranging from +2500 div. to +5000 div.

You can return to the default value of 0 divisions trigger delay by pressing the TRIG DEL key and then the RESET key simultaneously.

In digital mode on the PHILIPS PM3377, menus for various functions and measurements are accessed via the five softkeys located below the CRT. The top text area of the screen shows calculation information and channel settings, while the bottom text area shows the functions assigned to the five softkeys.

• MAIN MENU: This is the top-level menu. From here you can access:
– CURSORS: Activates the cursors menu for measurements.
– SETTINGS: Displays the vertical and time base settings relating to the displayed traces.
– PROCESS: Activates the menu for AVERAGE or ENVELOPE functions.
– MEMORY: Activates the menu for managing front panel settings and waveform registers.
– TEXT-OFF: When pressed, all text disappears from the screen. The text is placed on the screen again by pressing one of the five softkeys.

• CURSORS menu: Once activated, two cross-shaped MAIN CURSORS are positioned on the waveform. You can move them horizontally and vertically. The small LOCATE cursors are placed on the waveform to indicate exactly where on the waveform the selected automatic measurement is being calculated.

• CALCULATE menu: From the Cursors menu, you can enter the CALCULATE menu. Here you can select AMPLitude or TIME measurements.

• ZOOM menu: This menu is used to magnify a part of the signal while retaining full sample resolution over the selected part.

• PROCESS menu: Define which of the two processes, AVERAGE or ENVELOPE, is activated. They cannot be active at the same time.

• MEMORY menu: An intermediate menu used to choose between the FRONTS menu, REGISTERS menu and SHIFT menu.

To perform amplitude measurements on your PHILIPS PM3377, enter the CURSORS menu, then the CALCULATE menu, and finally the AMPL-softkey. The following selections can be made:

• Vpp (Peak-to-Peak): Calculates the peak-to-peak value of the signal part between the MAIN CURSORS. The LOCATE CURSORS indicate the signal top and bottom the calculation is related to. The result is displayed in the right corner of the top text area.

• ABS (Absolute): Calculates the vertical voltage differences between the dotted ground line and MAIN Cursor 1 (C1 value) and MAIN Cursor 2 (C2 value). The results are displayed in the top text area of the CRT.

• RMS (Root Mean Square): Calculates the Root Mean Square value of the waveform between the MAIN cursors. This value is referenced to the dotted ground line. This line can be vertically positioned by grounding (GND key) the relevant channel and then adjusting Y POS to the desired vertical position. The calculation will start again when the GND is released.

• MEAN: Calculates the mean value of the waveform between the MAIN cursors. This value is referenced to the dotted ground line, which can be positioned as described for RMS mode.

To perform time measurements on your PHILIPS PM3377, enter the CURSORS menu, then the CALCULATE menu, and finally the TIME-softkey. The following selections can be made:

• FREQUENCY: Calculates the signal frequency, provided that at least one signal period is present between the MAIN cursors. The LOCATE cursors indicate the signal period over which the calculation is made.

• PERIOD: Calculates the duration of one signal period, provided that at least one signal period is present between the MAIN cursors. The LOCATE cursors indicate the signal period over which the calculation is made.

• WIDTH: Calculates the width of the first pulse seen from the left cursor, provided that there is at least one pulse present between the MAIN cursors. The pulse may be negative- or positive-going. The LOCATE cursors indicate the signal part over which the calculation is made.

• RISE: Calculates the rise- or fall-time (“tr”) of the first signal slope seen from the left cursor, provided that there is at least one slope between the MAIN cursors. The 100% level is taken to be the vertical value between the MAIN cursors. The rise time is automatically calculated between the 10% and 90% level of the dV-amplitude or to the nearest sample to these points.

The ZOOM and AUTO ZOOM functions on the PHILIPS PM3377 are used to magnify a part of a signal while retaining full sample resolution over the selected part.

ZOOM

If a part of the signal needs to be examined in more detail, the ZOOM function can be used. The main cursors can be set on the wanted trace and on the signal part of interest, using the CURSOR SELECT menu and the CURSOR CONTROL menu.

Then, by entering the ZOOM menu and activating the RESTART function, if within the limit of time base and delay range, a new acquisition will be made in the adapted time base setting and delay time. This means that the selected part is resampled using full memory and at a higher sample rate, so higher resolution is used only on the part of interest.

• REVERSE: Resamples at the previous settings (this function is only active after use of the RESTART function).

• CENTER: Sets the MAIN cursors horizontally to +2 DIV and -2 DIV from the screen centre.

AUTO ZOOM

In this mode, it is possible to simulate the operation of a delay time-base function by displaying a main time-base signal and a delayed time-base signal together on the screen.

The main time-base signal is stored in one of the register memories. First select one of the register memories by pressing the MEMORY and REGISTERS softkeys. Now load the signal to be examined into the selected register memory and display this on the screen. Move the live signal away from the stored signal by use of the channel position control.

When AUTO ZOOM is activated, the MAIN CURSORS are set on the stored signal and the LOCATE CURSORS on the live signal. These cursors indicate the part of the signal that is displayed in more detail and can be shifted across the screen or the time-base can be expanded up or down by means of the softkeys.

The PHILIPS PM3377 allows you to compare a live signal with a stored reference waveform. The register memories R1, R2, and R3 make it possible to store different waveforms in the oscilloscope memory. These signals remain stored after power down and can be displayed on screen whenever needed.

1. First select one of the register memories with the REGISTERS menu. This menu is entered by pressing the MEMORY softkey and then pressing the REGISTERS softkey.

2. Now load a reference signal into the selected register memory by pressing the LOAD key. In this way, all three register memories can be selected and filled with reference signals.

3. Now a measured “live” signal (R0) can be compared with one of the stored reference signals by displaying the signals on screen simultaneously.

The measured signal can be moved on the screen by means of the Y POS rotary knob. But when the instrument is in the LOCK-mode, the measured signal and the stored signal can be moved on the screen by using the SHIFT function.

The PHILIPS PM3377 has facilities to make a hard copy of the information on the CRT via a plotter or a printer. The plot out can consist of the recorded waveform(s), the belonging oscilloscope settings, the trace identification, cursors, results of measurements and a measuring graticule. Different options exist depending upon the version of the oscilloscope.

All set up actions are done under the APPLICATION preselect menu which can be entered by performing the following action: press the front panel key MENU and keep it pressed. Then press AUTO SET. After this the APPL softkey must be pressed. Selected parameters are visible in the top text area of the CRT.

The plot action is started by pressing the front panel PLOT key. Please note that during the plot action the signal acquisition stops and all softkeys are inactive. Plotting can be stopped by pressing the PLOT key again.

• Analog Plot Out to XY Recorders: This mode is possible for all versions. It can plot the waveform(s), channel identification, and measuring graticule. Access the service menu (press and hold MENU, then press AUTO SET), press APPL, then PLOT-KEY until “plot analog” appears, then press PLOT. Use the PLOT-A softkey to access the set up menu for PLOTSPEED and PENLIFT.

• Plot and Print via IEEE-488 Interface (version /40): This allows digital plotting and printing. Set up the interface via the service menu (APPL > IEEE). Then, use the PLOT-KEY to select “plot-digital” or “printer” and press the PLOT key to start.

• Plot and Print via RS-232C Interface (version /50): Similar to IEEE-488, but setup is done via the RS-232C menu (APPL > RS232) to configure BAUD RATE, PARITY, etc. Then, use the PLOT-KEY to select the plot/print action and press the PLOT key.

The Application Preselect Menu on the PHILIPS PM3377 contains a number of operating functions that do not need to be entered frequently. These functions relate to SINGLE SHOT mode, TV triggering and adjustment of plotter/printer and interface parameters.

Proceed as follows to enter the APPLICATION PRESELECT menu:

1. Press MENU and keep it pressed. Now also press AUTO SET.

2. Now the Service menu has been entered, the LCD should indicate “***”.

3. Press APPL, which is one of the CRT softkeys.

4. The CRT should indicate “APPLICATION PRESELECT MENU” on the upper side of the screen.

The selections are made with the softkeys under the CRT. The selected functions are displayed in the top text line of the CRT.