FA-2 Frequency Counter User Manual

Contact Information

For assistance, contact:

WUTONG electronic
Longhua Shenzhen Guangdong CHINA

Website: http://bg7tbl.taobao.com

TEL/WeChat: 134 2795 9750

QQ: 1630 2767

Email: BG7TBL@GMAIL.COM / BG7TBL@QQ.COM / BG7TBL@126.COM

Date: 2021-01-07

Table of Contents

• 1. Key Features
• 2. Overview
• 3. Specifications
• 4. Installation and Usage
  • 4.1 Rear Panel
  • 4.2 Front Panel
  • 4.3 LCD Display Data
• 5. Block Diagram
• 6. Frequently Asked Questions (FAQ)

1. Key Features

• High speed, high precision, up to 11 valid digits/second @10MHz.
• CH2 input up to 6GHz.
• High precision OCXO inside, can connect external 10M frequency source.
• With data statistics function, displays average, max, min, peak-to-peak frequency.
• USB port for PC connection and data processing, compatible with HP53131 mode.
• CH1 with power meter function, dynamic range up to 60dB.

2. Overview

The FA-2 frequency counter is a high-precision, high-speed instrument with statistical functions. It can automatically record input frequency data, facilitating long-term monitoring of external frequency changes. Channel 2 can measure frequencies up to 6 GHz. It features a built-in OCXO and can also accept an external 10M frequency standard.

3. Specifications

CH1 Specifications:

• Frequency Range: 1Hz-200MHz
• Input Impedance: 50 OHM / 1M OHM
• Input Sensitivity: 50 OHM: 25mVrms-2Vrms; 1MR: 25mVrms-2Vrms
• Frequency Accuracy: 0.1s gate: 0.001Hz@10M; 1s gate: 0.0001Hz@10M; 10s gate: 0.00001Hz@10M
• Test Speed: 12digits/second@100M-200M; 11digits/second@10M-99.999999M; 10digits/second@1M-9.999999M; 9digits/second@0.1M-0.999999M; 8digits/second@90K-99K; 8digits/second@1Hz-89.999K
• Power Measurement Range: -50dBm-+20dBm, 1M-550M@50 OHM
• Power Accuracy: 0.5dB@10MHz
• Interface Type: BNC

CH2 Specifications:

• Frequency Range: 30MHz-6GHz
• Input Impedance: 50 OHM
• Frequency Accuracy: 0.1s gate: 1Hz@1GHz; 1s gate: 0.01Hz@1GHz; 10s gate: 0.001Hz@1GHz
• Input Power Range: -20dBm-+13dBm@0.5-5G
• Interface Type: SMA

General Specifications:

• Gate Time: 0.1S/1S/10S
• Internal Frequency Standard: 10MHz
• Internal Frequency Standard Type: OCXO
• Internal Frequency Standard Aging: 0.5Hz/year
• 10M Frequency Output Power: 4dBm
• External Frequency Input Range: 0dBm to +20dBm
• Operating Modes: CH1 Frequency, CH1 Statistics, CH2 Frequency, CH2 Statistics
• Front Panel Functions: MODE (change mode), GATE (change gate time), RST (restart test), CH1 input, CH2 input.
• Rear Panel Functions: 10M REF INPUT (external 10M input), 10M REF OUTPUT (10M output), USB port, STD ADJ (inside OCXO frequency adjust), Power switch, DC plug.
• Statistics Mode Data Type: average, max, min, p-p
• Power Supply: DC11.7-12.5V (startup: <0.4A, stabilize: <0.2A)
• Dimensions (L*H*D): 106*55*105mm
• Weight: 350g
• Accessories: DC12V adapter (1PCS)

4. Installation and Usage

4.1 Rear Panel

The rear panel features:

• 1. 10MHz Frequency Standard Input and Output (BNC connectors).
• 2. USB Port: Uses an FT232RL chip. USB drivers can be downloaded from the FTDI website.
• 3. Internal OCXO Frequency Adjustment.
• 4. Power Switch (ON/OFF).
• 5. DC 12V Input.

4.2 Front Panel

The front panel includes:

• 1. 12864 LCD Display.
• 2. MODE Key: Switches between operating modes.
• 3. GATE Key: Changes the gate time.
• 4. RST Key: Restarts the measurement. RST+GATE can open/close the CH1 low-pass filter. RST+MODE selects CH1 impedance (50R/1MR).
• 5. CH2 Input (BNC connector).
• 6. CH1 Input (BNC connector).

4.3 LCD Display Data

The LCD displays various information depending on the mode:

• CH1 Frequency Mode: Displays CH1 frequency, input power, units (Hz, kHz, MHz), gate time, frequency standard status (internal/external), and CH1 input impedance (1MR/50R). The gate status is indicated by an asterisk (*).
• CH1 Statistics Mode: Displays the number of statistics points, current frequency, average value, maximum value, minimum value, and peak-to-peak value. It also shows the gate time, frequency standard, and LPF status.
• CH2 Frequency Mode: Displays CH2 frequency, gate time, and frequency standard status. An asterisk (*) indicates high precision mode for CH1.
• CH2 Statistics Mode: Displays statistics for CH2, similar to CH1 statistics mode.

5. Block Diagram

A block diagram illustrates the internal components and connections of the FA-2 frequency counter, including the DC-DC converter, LDO, OCXO, EFC, CPLD, MCU, FT232 USB interface, LCD, and various input/output connectors.

6. Frequently Asked Questions (FAQ)

• Q: How can I know if the machine is good?
  A: Connect the 10M output from the rear panel to CH1. The LCD should display 10M, indicating the counter is functioning correctly.
• Q: What to do if the low frequency measurement is unstable or inaccurate?
  A: Open the Low Pass Filter (LPF).
• Q: Can I use an oscilloscope probe as a test probe?
  A: It is not recommended. Standard oscilloscope probes (X1 setting) have a limited frequency range and high impedance (X10), which can cause impedance mismatch, signal attenuation, and inaccurate measurements.
• Q: What is the application of the USB port?
  A: The USB port is used for communication and allows control of the frequency counter via a PC.