振荡器模拟.pdfVIP

12 This chapter shows the basics of simulating oscillators to determine several basic specifications. Lab 12: Oscillator Simulations Lab 12: Oscillator Simulations About this lab exercise: This lab exercise is in two parts: Part 1: You use a prebuilt example oscillator file and perform one simulation. Part 2: You build an VHF VCO and preform several simulations. OBJECTIVES Use OscTest Element to get frequency and S-parameter information. Build an oscillator and simulate numerous performance tests. PART 1: PROCEDURE – Oscillator Example 1. Create a new project named: oscillator 2. Copy the example design into your directory From the Main window, use the Copy Design command. When the dialog box appears, browse the example directory and copy from: examples \ tutorial \ LearnOSC_prj \ networks \ Osctest_VCO.dsn To Path: oscillator_prj \ networks\ 3. Open the new oscillator schematic design a. Zoom in on the device and notice that it has two emitters. You can remove the pin labels in the Pin/Tee tab of the OptionsPreferences dialog. Notice that the unconnected emitter is showing red (unconnected pin) – this is OK. OstTest is used to determine if the circuit oscillates. 12-2 Lab 12: Oscillator Simulations b. Notice the OscTest component is named: OscTickler. Go to the S- parameter palette and locate this component. Basically, this component is an S-parameter simulation controller specifically designed to be inserted in series with the resonator. Therefore, you can simulate without another controller or ports. 4. Simulate (dataset name: osc_test) and Display the results a. Open a data display (save as: osc_basics) and plot S-11 on a polar plot. b. Put a marker on the trace where it crosses zero on the x-axis as shown. Whi