how to adjust LO frequency to control IF output frequency

सामान्य प्रश्न: Can the LO frequency of the downconverter be modified (जैसे, से 1750 मेगाहर्ट्ज से 875 मेगाहर्ट्ज या 750 मेगाहर्ट्ज)?

क्यू: नमस्ते, can the down converters we bought from you be modified to cut the LO frequency in half? They currently operate at 1750 MHz—can they work around 875 MHz or be set to 750 मेगाहर्ट्ज?

ए: हाँ, the LO (स्थानीय थरथरानवाला) frequency can be modified. तथापि, we strongly recommend that the modification be carried out by our engineers, or that you return the unit to us for adjustment to ensure optimal performance and stability.

If you prefer to modify it yourself, it is also possible by following the procedure below.

---

🔧 Self-Modification Guide

1. Hardware Setup

• Open the metal enclosure of the FDC (फ्रीक्वेंसी डाउन कन्वर्टर).
• Connect the device to your computer using a USB-to-TTL adapter.

Wiring (3 connections only):

• TX → RX
• RX → TX
• GND → GND

You may also make the cable yourself if needed.

---

2. Software Control via Serial Port

Use a serial terminal tool to send commands to the module.

---

3. Check Current Status

Command:

check?

विवरण:

• Returns the current operating status and detected frequency values.

महत्वपूर्ण:

• The command must end with a question mark (?), otherwise it will be invalid.

---

4. Modify LO Frequency

You can adjust the LO frequency by sending the following commands:

Target_FRE1=XXXX;
Target_FRE2=XXXX;
Target_FRE3=XXXX;

स्पष्टीकरण:

• XXXX = desired frequency value (इकाई: मेगाहर्ट्ज)
• Each command corresponds to a specific LO module (LE1 / LE2 / LE3)
• The system will automatically relock to the new frequency after setting

उदाहरण:

• Set LO to 875 मेगाहर्ट्ज:

Target_FRE1=875;

• Set LO to 750 मेगाहर्ट्ज:

Target_FRE1=750;

महत्वपूर्ण:

• Each command must end with a semicolon (;), otherwise it will be invalid.

---

⚠️ Important Notes

• Ensure the target LO frequency is within the supported operating range of the hardware.
• Changing the LO may affect IF output frequency and system performance.
• Improper configuration may lead to signal instability or loss of lock.

---

✅ Recommendation

For best results and to avoid potential issues, we recommend:

• Contacting our engineering team for guidance, या
• Returning the unit to us for professional modification and calibration

---

If you have any questions or need the configuration software, feel free to contact us.

सामान्य प्रश्न

If you need to adjust the LO (local oscillator) range of the downconverter, you must first remove the bottom screws and open the top cover of the downconverter. Only then will you be able to access the internal connector and plug in the USB-to-UART adapter.

क्यू: What are TX and RX? I cannot find them on the converter.

ए: TX and RX are standard UART communication signals:

• टेक्सास (संचारित): data output from the device
• RX (Receive): data input to the device

They are not separate modules; they are already labeled on the interface pins of the converter.

क्यू: What pins are available on the connector?

ए: The connector has four pins:

• जी.एन.डी – Ground
• टेक्सास – Transmit
• RX – Receive
• 3.3वी – Power supply (NOT 5V)

क्यू: How should I wire it correctly?

ए: Please connect as follows:

• GND → GND
• TX → RX (cross connection)
• RX → TX (cross connection)
• 3.3V → Power supply input (from USB-to-UART adapter or regulated 3.3V source)

⚠️ Important: TX and RX must be crossed; otherwise, communication will not work.

क्यू: Can I use 5V power?

ए: ❌ No, 5V is not allowed.
✔ Only 3.3V power supply समर्थित है.

Using 5V will damage or burn out the downconverter.

क्यू: Can I power it via USB?

ए: हाँ. If your USB-to-UART adapter provides a stable 3.3वी आउटपुट, तुम कर सकते हो:

• Use USB 3.3V to power the downconverter
• Connect TX / RX / GND for communication

क्यू: Software usage

ए: After correct wiring, आप उपयोग कर सकते हैं SSCOM software to:

• Open the serial port
• Communicate with the device
• Adjust the local oscillator (एलओ) frequency and other parameters

Important safety notes ⚠️

• Ensure the connector is inserted in the correct orientation
• Do NOT plug it in backwards
• Do NOT use 5V power
• Incorrect wiring may permanently damage the downconverter