BK PRECISION 4007DDS manual 电路图.pdf

1 Model 4007DDS 7 MHz Sweep Function Generator RadioFans.CN 收音机爱 好者资料库 Model 4007DDS - Instruction Manual 2 Limited Two-Year Warranty B 8.3 inch (210 mm) deep; 3.5 inch (88 mm) high, without bumpers. WEIGHT.Aprox 2 kg REGULATORY STANDARDS . .IEC 1010-1, Insulation category II, Pollution Degree 2. EMC.EN50081-1 and EN50082-1. CE Labeled NOTES .Specifications apply at 255C ambient temperature and after 30 minutes warm up. Specifications are subject to change without notice. For the most current product information please visit . 1.4 TECHNICAL SUPPORT Ifthis product fails to operate upon arrival, contact your B 20V peak-to-peak into open circuit or 10V peak-to-peak into 50 ohms. 12.SYNC OUT A square wave with TTL levels in phase with the main output. Useful for synchronization ofexternal devices. 13.SWEEP The ON selects the Linear, Logarithmic sweep. The SET selects the START and STOP frequencies ofthe seep and also the RATE repetition ofthe sweep selected. Front Panel View 11 3.2 INSTRUMENT INPUTS AND OUTPUTS The Model 4007 main output impedance is 50. The output can deliver up to 10V peak-to-peak waveforms into a 50 load. Proper signal loading and connection is necessary for the generator main output to meet its specifications. An RG-58 coaxial cable equipped with BNC connectors and terminated with a 50 feed through termination is recommended. Using the 50 terminator minimizes signal reflection and power losses on the line due to the impedance mismatch. At higher frequencies, an un-terminated or improperly terminated output will cause aberrations on the output waveform. Impedance Matching Ifthe waveform generator is driving a high impedance, such as the 1 M input impedance ofan oscilloscope vertical input, connect the transmission line to a 50 ohms attenuator or a 50 ohms termination and to the oscilloscope input. The attenuator isolates the input capacitance ofthe device and terminates the waveform generator properly. 3.3 SYNC OUTPUT A square wave output signal at the main output frequency is available at this output, producing TTL levels with a 50 source impedance. This output is protected from short circuit and can drive a minimum of20 TTL loads. Leads connected to the SYNC OUT should be as short as possible to prevent rounding ofthe TTL pulse. The SYNC output signal symmetry is changed by using the DUTY CYCLE control for all selected waveforms. 3.4 FIRST TIME OPERATION The following exercise will familiarize the operator with most functions ofthe Model 4007 function generator. Preset the controls as follows: WAVEFORM.SINE DUTY CYCLE.OFF OFFSET.OFF ATTENUATOR.OFF AMPLITUDE.CENTERED Connect a 50 coaxial cable, terminated into a 50 feedthrough, to the vertical input ofan oscilloscope (set vertical to 2V/Div and horizontal to 1 ms/Div). The oscilloscope should display a triangle waveform. Model 4007DDS - Instruction Manual 12 1.Alternately press the sine, square and triangle pushbuttons and observe the different wave shapes. Return to the sine function. 2.Rotate the frequency knob and press up and down range switches while observing the change in frequency ofthe displayed waveform. 3.Push the DUTY CYCLE ON button. Select the SQUARE wave. Rotate the control while observing the change in the duty cycle ofthe waveform 4.Alternately press the 20 dB attenuator button and rotate the AMPLITUDE control to verify that the waveform amplitude changes. Return these controls to the preset condition. 5.Push the OFFSET ON button and rotate the OFFSET control. Notice the change in DC level ofthe displayed waveform. Return these controls to the preset condition. 3.5 DETAILED OPERATING INSTRUCTIONS 3.5.1 Frequency Setting The frequency ofthe generator is changed by turning the FREQUENCY control. The frequency range is selected by pressing the up or down range pushbuttons. The waveform output frequency is shown on the LCD display. 3.5.2 Variable Symmetry The symmetry ofthe Square waveform can be changed by pushing the DUTY CYCLE ON button and rotating the DUTY CYCLE knob. A change ofsymmetry from 15% to 85% can be obtained. 3.5.3 Output Attenuation The pushbutton attenuator of20 dB attenuates the waveform by a factor of10. In order to achieve low noise waveforms at low levels, use proper attenuation and keep the amplitude control far from its maximum CCW position. 3.5.4 Offset Output DC voltage appears at the main output by pushing the OFFSET ON button. By rotating the OFFSET control knob from CCW to CW, the output level and polarity are changed from negative to positive. This level is also controlled by the output attenuator. DC offset is achieved by adding the above DC output to any ofthe output waveforms selected by pressing the function buttons. A maximum open circuit offset voltage of10V can be obtained. It should be noted that the peak voltage ofthe signal, including DC and AC cannot exceed 10V into open circuit and 5V into 50. The maximum current which can be taken from the output in DC or AC modes is limited to 100 mA maximum. 3.5.5 Sweep Operation The internal sweep mode allows an overview ofthe frequency sensitive characteristics ofa device under test. In the mode the frequency ofthe selected waveform is swept from the selected start to selected stop frequency. When the stop frequency is reached, the instrument resets to the start frequency, and repeats. The SWEEP SET pushbutton selects the setting ofthe sweep START, sweep STOP and sweep RATE by using the main frequency control. The parameter being selected is displayed on the LCD. The SWEEP ON pushbutton selects the linear or logarithmic sweep and the sweep OFF. 13 Model 4007DDS - Instruction Manual 14