![Impedance analyzer with external clock](https://kumkoniak.com/72.jpg)
They have a +/- 2.5 ppm frequency stability with a +/- 3 ppm mechanical trim adjust on top. These Vectron oscillators have decent specifications for such a low cost and small package. These are available for $6 (for two) on eBay from the seller "rfextra." They appear to have a custom part number, but the datasheet for the "OSC Series" of oscillators from Vectron covers this model. The clock oscillator used here is a Vectron T-1115-10M0 miniature 10 MHz TXCO. If this is not sufficient, the 33 ohm series resistor can be replaced with a low-impedance coupling capacitor (0.01 ♟). For a 50 ohm line, with a 50 ohm load at the end of that line, the 50 ohm load will receive a 2.5 volt peak-to-peak square wave. The reflected signal will be dissipated in the series 33 ohm resistor plus the internal resistance of the 7SZ04 driver (approximately 17 ohms). A 33 ohm resistor is shown as a series element in each output.įor a 50 ohm line, with a high impedance load at the end of that line, the mismatched load will create a reflection. Each output is 5 volt CMOS that can drive a 50 ohm line that is terminated with either a high impedance load or 50 ohms.
![impedance analyzer with external clock impedance analyzer with external clock](https://euro-techfe.com/wp-content/uploads/hioki-im7581Main.jpg)
The master oscillator module contains a 10 MHz clock oscillator and three 7SZ04 buffered line output drivers (Digi-Key Part: NC7SZ04M5XCT-ND). Also, the 1024 MHz second local oscillator for my version of the spectrum analyzer will be done using a Mini-Circuits KSN-1024A+ fixed oscillator and it requires a 10 MHz reference input. The Analog Devices AD9851 may be a better "drop in" choice. The overall phase noise will also be slightyly increased by using the multiplier, but should be well within spec. Since the DDS is programmed to output a 10.7 MHz signal, the minimum internal clock frequency is 21.4 MHz (Nyquist), so the 40 MHz should work out quite well.
![impedance analyzer with external clock impedance analyzer with external clock](https://www.sinosonics.com/wp-content/uploads/2021/04/Impedance_Analyzer_4.jpg)
The recommended Analog Devices AD9850 DDS has an (undocumented) internal 4x multiplier which can be used to convert the 10 MHz external clock into a 40 MHz internal clock. The MSA software has a setting for changing the clock oscillator frequency, and it looks like 10 MHz will work, but this hasn't been tested yet. The main difference here is using a 10 MHz Temperature Compensated Clock Oscillator (TCXO) instead of the recommended 64 MHz clock oscillator.
![impedance analyzer with external clock impedance analyzer with external clock](https://www.minervaelektronik.com.tr/wp-content/uploads/2017/01/6630-%E6%AD%A3%E9%9D%A2-600x250.jpg)
![impedance analyzer with external clock impedance analyzer with external clock](https://ae01.alicdn.com/kf/HTB1Lam7iP3z9KJjy0Fmq6xiwXXaK/Direct-60C-antenna-analyzer-standing-wave-impedance-analyzer-RFID-radio-frequency-antenna-detection-short-wave-nature.jpg)
The original MSA oscillator design is SLIM-MO-64. This is my version of the master clock oscillator for Scotty Sprowls' Modularized Spectrum Analyzer (MSA) project. Scotty's Spectrum Analyzer - Master Clock Oscillator
![Impedance analyzer with external clock](https://kumkoniak.com/72.jpg)