3010 Prescaler Operating & Service Manual

AZD Technology LLC ~ Albuquerque, NM 87112

www.azdtechnology.com

Copyright © AZD Technology L.L.C. All rights reserved.

TABLE OF CONTENTS

Section                         Title                                                                                                      Page

SECTION 1, GENERAL INFORMATION.................................................................................................................................. 2

1.1        Introduction............................................................................................................................................................ 2

1.3        SPECIFICATIONS.......................................................................................................................................................... 2

SECTION 2, INSTALLATION..................................................................................................................................................... 2

2.1        Introduction............................................................................................................................................................ 2

2.3        Initial Inspection................................................................................................................................................... 2

2.5        Power Requirements........................................................................................................................................... 3

2.7        Power Cable.............................................................................................................................................................. 3

2.9        Ventilation................................................................................................................................................................ 3

SECTION 3, OPERATION............................................................................................................................................................ 3

3.1        Introduction............................................................................................................................................................ 3

3.3        Frequency Measurement................................................................................................................................... 3

3.10      Phase Locked Loop Application.................................................................................................................. 6

Section 4, Performance Tests....................................................................................................................................... 6

4.1        Introduction............................................................................................................................................................ 6

4.3        Test Equipment......................................................................................................................................................... 6

4.8        RF Input Power......................................................................................................................................................... 7

4.11      F/10 Output Levels.................................................................................................................................................. 7

Section 5, Service................................................................................................................................................................... 8

5.1        Introduction............................................................................................................................................................ 8

5.5        Theory of Operation........................................................................................................................................... 9

5.7        PIN Diode Attenuator........................................................................................................................................ 10

5.14      Automatic Level Control............................................................................................................................. 10

5.19      Modulated RF......................................................................................................................................................... 11

5.21      Threshold Comparator................................................................................................................................. 11

5.23      Overload Comparator................................................................................................................................... 11

5.25      Power Supplies...................................................................................................................................................... 11

5.27      Test Points............................................................................................................................................................... 12

Section 6, Replacement Parts..................................................................................................................................... 17

6.1        Introduction.......................................................................................................................................................... 17

6.3        Printed Circuit Board Assemblies.......................................................................................................... 17

6.4        Cabinet Components & Hardware........................................................................................................... 17

SECTION 1, GENERAL INFORMATION

1.1              Introduction

1.2              This manual provides information about the installation, operation, testing, and maintenance of the AZD Technology 3010 Prescaler.

1.3              SPECIFICATIONS

Input

Frequency Range: .1 to 1 GHz (useable up to 1.1 GHz and down to 50 MHz)

Sensitivity: -27 dBm at 0.10 GHz, -26 dBm at 0.50 GHz, -23 dBm at1.0 GHz (+/- 1 dBm tolerance)

Coupling: DC (INPUT & OUTPUT)

Input Return Loss: greater than 10 dB (less than 1.9 SWR), .1 to 1 GHz (50 ohms nominal)

Overload: 630 uW (-1 dBm) at 0.10 GHz, -6 dBm) at 0.50 GHz, -7 dBm at 1.0 GHz, (+/- 1 dBm tolerance).

Attenuator: Bridged-Tee configuration using PIN diodes.  Attenuation is set automatically by an internal automatic level control.

AM Tolerance: 48 % from 0.10 to 1.0 GHz

Output

TTL Level: 1.6 to 3.2 volts peak to peak with 50-ohm termination

Scale Factor: 0.1 (F/10)

General

Operating Temperature Range: 0 to 50 degrees C

Power Requirements: 105V to 125 VAC, 60 Hz AC, 3.7 Watts nominal, 5.4 Watts maximum.

Overall Dimensions: 8.125 wide X 7.0 deep X 3.875 high (inches)

Weight: 2.5 Pounds

SECTION 2, INSTALLATION

2.1  Introduction

2.2  This section provides information necessary to install the 3010 Prescaler.  Initial inspection, AC power requirements, and ventilation are covered in this section.

2.3  Initial Inspection

2.4  Inspect the cardboard box for damage. If the cardboard box or foam plastic is damaged, it should be kept until the 3010 prescaler has been checked for mechanical and electrical damage.  Notify AZD Technology if the box contents are not complete, if there is mechanical defect, or if the 3010 Prescaler does not pass the electrical performance tests.  Notify the carrier, if the shipping container or foam plastic is damaged. Keep the shipping material for the carrier’s inspection.

2.5  Power Requirements

2.6  The 3010 Prescaler requires a power source of 115 +/- 10 VAC, 60 Hz.  Power consumption is 10 watts maximum.

2.7  Power Cable

2.8  The 3010 Prescaler is shipped with a standard three-wire AC power cable permanently attached.

2.9  Ventilation

2.10          To maintain adequate ventilation, provide at least 6 inches of clearance in front of each vented hole plug located on the right and left side of the 3010 Prescaler.

SECTION 3, OPERATION

3.1              Introduction

3.2              This section provides the information necessary to setup the 3010 Prescaler for use with a frequency counter or phase locked loop (PLL) application.

Figure 1, 3010 Prescaler Front Panel

3.3              Frequency Measurement

3.4              Before connecting to a frequency counter, make sure the 3010 Prescaler AC power switch is in the OFF position and the power cord is connected to a standard 3-wire 115 VAC outlet.

3.5              Connect the F/10 OUTPUT through a 50-ohm coaxial cable to the input of a frequency counter capable of accepting 10 to 100 MHz at 1.6 to 3.2 volts peak-peak.  If the counter’s input impedance is not 50 ohms, the 50 ohm feed-thru termination supplied with the 3010 Prescaler should be inserted between the counter and the coaxial cable from the F/10 OUTPUT.

3.6              If a frequency counter or oscilloscope does not provide a 50 ohm termination at its input, the 50 ohm feed-thru termination supplied with the 3010 Prescaler should be connected.  Figure 2 shows an oscilloscope trace resulting from a 48 inch length of RG58A/U coax cable driven by the 3010 Prescaler F/10 OUTPUT.  The oscilloscope’s vertical input is terminated with a 50 ohm feed-thru.

Figure 2, Terminated Coax Cable

3.7              Figure 3 shows an oscilloscope trace with the 50 ohm feed-thru termination removed.  Because of reflected power from the un-terminated end of the cable, ringing and over/under shoot are present on the waveform.  The shape of the waveform will change with frequency and cable length.

Figure 3, Un-terminated Coax Cable

3.8              Place the AC power switch in the ON position before a RF signal is connected to the 3010 Prescaler RF INPUT.  Use a 50-ohm coaxial cable to connect a RF signal generator to the 3010 Prescaler INPUT.

3.9              A signal level approximation between 50 microwatts (-13 dBm) and 25 microwatts (-16 dBm) provides adequate power to drive the 3010 Prescaler for scaling frequencies between .1 to 1.0 GHz.  If the OVERLOAD indicator is illuminated, the RF signal level approximation is on the high side and a reduction in signal level is required.  To attenuate the RF signal, add a 50 ohm coaxial attenuator to the coaxial cable connected to the 3010 Prescaler RF INPUT.  No display on the frequency counter indicates the signal power approximation is on the low side and the signal level from the RF source needs to be increased or attenuation removed.  After the signal level requirements are satisfied, a frequency measurement can be preformed.  The reading on the frequency counter multiplied by 10 is the frequency of the VHF/UHF signal connected to the 3010 Prescaler RF INPUT.

3.10          Phase Locked Loop Application

3.11          Figure 4 shows a typical phase locked loop application.

Figure 4, Phase Locked Loop Application

3.12          Circuit operation is as follows.  To phase lock the 1050 source, approximately 25 microwatts of RF power is coupled to the INPUT of the 3010 Prescaler.  The 1050 output frequency is scaled first by the Prescaler reducing a 950 MHz signal to 95 MHz and then scaled again (F/N) by a 54/74S TTL divider.  If N = 100, the frequency at the phase detector will be 950 KHz which can be processed by most commonly available phase detectors.  If the output of the CD4527 BCD Rate Multipliers is 950 KHZ, the loop will lock when the error voltage produced by the phase detector forces the phase of the 1050 Generator divided by 10N to match the output of the BCD Rate Multiplier.

Section 4, Performance Tests

4.1              Introduction

4.2              Performance evaluation of the 3010 Prescaler is accomplished by comparing measured data created with the test equipment specified in paragraphs 4.5 through 4.7 against the data of paragraphs 4.10 through 4.13.

4.3              Test Equipment

4.4              The test equipment required for performance evaluation of the 3010 Prescaler is given in paragraph 4.5 through 4.7.

4.5              RF signal Generator Requirements

4.6              Frequency Counter Requirements

4.7              Oscilloscope Requirements

4.8              RF Input Power

4.9              The table of paragraph 4.10 gives typical RF INPUT power limits as a function of frequency for the two parameters monitored by the Automatic Level Control (ALC) circuit.  For the overload comparator, the upper trip point (increasing power level) and lower trip point (decreasing power level) differ by 3.75 % in power level, and the difference for the threshold comparator is 14.55 %.

4.10          3010 Prescaler RF Input Power Limits

4.11          F/10 Output Levels

4.12          The table of paragraph 4.13 gives typical output voltage levels as a function of frequency.  Since the output is a rectangular waveform and contains harmonics, the bandwidth of the oscilloscope or True-RMS Voltmeter has an effect on the measurement accuracy.

4.13          3010 Prescaler F/10 Output Levels

Section 5, Service

WARNING

LINE VOLTAGE IS EXPOSED WITHIN THE 3010 PRESCALER EVEN WHEN THE POWER SWITCH IS IN THE OFF POSITION.  UNPLUG THE 3010 POWER CORD FROM THE AC POWER OUTLET TO FULLY UNPOWER THE INSTRUMENT.

5.1              Introduction

5.2              This section contains information needed to service the 3010 Prescaler.

Figure 3, 3010 Prescaler Back Panel

5.3              Before removing the fuse, turn off and unplug the unit.  To remove the fuse from the fuse holder, push in and twist the fuse holder cap section counter-clockwise approximately 45 degrees and pull straight back.  The fuse is held in the fuse holder cap section by spring contacts and should be pulled out of the cap section for inspection.

5.4              Turn off the unit and unplug the AC power cord. Remove the six 6-32 machine screws (one on each side, two front and back edges) that hold the cabinet top to the base and pull the top straight up and off to gain access to the circuit assemblies and components.

Figure 4, 3010 Prescaler Inside View

5.5              Theory of Operation

5.6              The theory of operation is organized in such a way that a block diagram, Figure 5, and circuit diagrams, Figure 6 and 7 are referred to during the explanation of each major component.

Figure 5, 3010 PRESCALER BLOCK DIAGRAM

5.7              PIN Diode Attenuator

5.8              A RF signal applied to the RF INPUT Connector is first coupled to a PIN Diode Attenuator capable of attenuating RF without introducing reactive components that create a mismatch (high VSWR).  The attenuator is placed ahead of the broadband RF amplifier to keep it from being overdriven during a frequency measurement.

5.9              The signal from the PIN Diode Attenuator is coupled to a Microwave Monolithic Integrated Circuit (MMIC) having a gain of approximately 20 dB from 0.01 to 3 GHz.

5.10          The output of the MMIC drives a resistive power divider.  Half the power from the divider is coupled to the input of a 1.1 GHz ECL Prescaler IC, and the other half to a broad-band Schottky Barrier diode detector.

5.11          If a signal power greater than approximately 1 milliwatt (0 dBm) is connected to the RF INPUT, the PIN Diode Attenuator is driven to maximum attenuation by the ALC described in paragraphs 5.14 through 5.18, and the MMIC is driven into gain compression limiting the drive level to the ECL decade divider to approximately 1.1 volts peak to peak.

5.12          The output of the ECL Prescaler IC is one tenth the frequency of the signal from the MMIC therefore 0.1 to 1.0 GHz becomes 10 to 100 MHz which is in a range useable by the next stage which is a PECL to TTL Translator, U2 of Figure 9.

5.13          The TTL output of the translator is coupled to a 74S TTL 50 ohm line driver IC, U3 of Figure 9, which drives the 3010 Prescaler F/10 OUTPUT.

5.14          Automatic Level Control (ALC)

5.15          Next is a description of the Automatic Level Control that keeps the drive level at the input of the 1.1 GHz ECL Prescaler IC at the required level with a wide range of input signal levels -- 100:1 (20 dB) at 400 MHz and lower.

5.16          The DC output of the Schottky Barrier diode detector, D4 of Figure 9, referenced in paragraph 5.10 responds with a DC output proportional to RF input.  The DC output of this detector diode along with the DC output of a reference diode, D5 of Figure 9, is connected to a differential amplifier, U1 of Figure 7, and since the DC bias voltage on each diode is equal and canceled by the differential amplifier, only the DC created by the RF signal is amplified.

5.17          When a RF signal, 0.25 microwatt (-36 dBm) or less, is connected to the RF INPUT, the voltage difference between the detector and reference diodes is almost zero, and the differential amplifier output provides almost 0 VDC to the error amplifier which forces the PIN diode driver to maintain the RF attenuator at the lowest attenuation condition.

5.18          When a RF signal is connected to the RF INPUT of the 3010 Prescaler and the power level is increased from 1 microwatt (-30 dBm) to 1 milliwatt (0 dBm), the amplified detector DC voltage starts at approximately 0 volts and increases as a function of RF INPUT power.  The error amplifier generates an output voltage proportional to the difference between a current generated by a fixed voltage (-12 VDC and R9 of Figure 7) and a current generated by the amplified detector voltage (U1 pin 6 and R10 of Figure 7).  The output voltage from the error amplifier drives the PIN diode driver (Q1, U3, and Q2 of Figure 7) which produces separate currents for each PIN diode in a direction that produces more or less RF attenuation as required.  This process keeps the drive level to the input of the ECL prescaler IC, U1 of Figure 9, at the required level over a wide input power range.

5.19          Modulated RF

5.20          When a modulated RF signal is applied to the 3010 Prescaler RF INPUT, the ALC will respond to the frequency of modulation, and the attenuation of the PIN Diode Attenuator is controlled at a rate equal to the modulation on the RF signal.  The ALC can respond to modulation frequencies up to 10 KHz.

5.21          Threshold Comparator

5.22          This comparator, U4B of figure 7, monitors the output of the differential amplifier, U1of Figure 7, and keeps the 74S TTL 50 ohm line driver output at a low logic level when a RF INPUT signal is not present.  When the RF INPUT signal reaches a preset threshold that is adequate to drive the ECL prescaler IC, the comparator removes drive to a switching transistor, Q1 of Figure 9, and the line driver input goes high so that the gate is allowed to drive the F/10 output.

5.23          Overload Comparator

5.24          This comparator, U4A of Figure 7, monitors the PIN diode driver.  When the input to the comparator reaches a preset DC level indicating maximum RF attenuation, a switching transistor, Q3 of Figure 7, is turned on and pulls current through a front panel LED.  No damage will occur at that point, but the maximum input power to the MMIC is 20 milliwatts (+13 dBm) and above that power level damage will occur.

5.25          Power Supplies

5.26          Three power supplies are required to power the circuits of the 3010 Prescaler.  All three power supplies (+5 volt, +12 volt, -12 volt) are located on the PS/ALC printed circuit assembly, Figure 6.  The center tapped secondary of the power transformer, T1 of Figure 10, allows the +5, and +12 regulator to be supplied from the filtered and unregulated DC from the positive side of the bridge rectifier, and the -12 volt regulator is supplied by the filtered and unregulated DC from the negative side of the bridge.  The ALC circuits use the +12 and -12 supplies only and the RF/Logic use the +5 and +12 supplies only.

5.27          Test Points

5.28          The following voltages are present at the designated test points for each of four test conditions.  The voltages of paragraphs 5.21 through 5.32 are measured on the PS/ALC printed circuit assembly.  The voltages of paragraphs 5.33 through 5.38 are measured on the RF/Logic printed circuit assembly.  Refer to Figure 6 and 7 for the location of each test point.

Figure 6, PS/ALC PCA Component Side

Figure 7, PS/ALC Circuit Diagram

5.20     Test Conditions

* 50 ohm termination connected to RF INPUT

5.21          Power Supply Measurements, Test Condition 1 (VDC)

5.22          Differential Input, Test Condition 1 (VDC)

5.23          Differential Input, Test Condition 2 (VDC)

5.24          Differential Input, Test Condition 3 (VDC)

5.25          Detector Amplifier Output, Test Point DA (VDC)

5.26          Error Amplifier Output, Test Point EA (VDC)

5.27          PIN Diode A Voltage, Test point A (VDC)

5.28          Pin Diode B Voltage, Test Point B (VDC)

5.29          PIN Diode R Voltage, Test Point R (VDC)

5.30          Threshold Comparator Output, Test Point S (VDC)

5.31          Overload Comparator Output, Test Point T (VDC)

5.32     Modulated RF Signal , Test Point DA (mVAC P-P)

Figure 8, RF/LOGIC PCA Component Side

Figure 9, RF Logic Circuit Diagram

5.33     PIN Diode A voltage, Test Point A (VDC)

5.34     Pin Diode B voltage, Test Point B (VDC)

5.35          PIN Diode R Voltage, Test Point R (VDC)

5.36          MMIC bias voltage, Test Point K (VDC)

5.37          U1 Pin 8, Test Point V (VDC)

5.38          Q1 input drive, Test Point S (VDC)

Figure 10, 3010 Prescaler Interconnections

Section 6, Replacement Parts

6.1              Introduction

6.2              Replacement Parts are available through the AZD Technology LLC web site www.azdtechnology.com

6.3              Printed Circuit Board Assemblies

6.4              Cabinet Components & Hardware

PRESCALER PAGE