Czerf CZE-05B - User Manual

CZERF
CZE-05B
FM transmitter
Please read this manual before you use the device, restore the manual
carefully in case you’ll need it in the future.

Summary

Attention Before Use

Main Characteristics

High-fidelity, High Stability Signal Transmission

Utilizes BH1415 chip, PLL, pre-emphasis, limiter, and low-pass filter for superior signal quality.

Stereo Clear Sound Quality

Employs AT89C2051, AT24C02, and power amplifiers for a 3D sound output effect.

Good Shielding Design

Close structural design minimizes external signal interference and frequency drift.

Excellent Heat Dissipation

High-quality aluminum alloy chassis ensures stability and continuous operation.

Easy to Use Interface

LCD display shows frequency; intuitive design for connection and adjustment.

Switchable Transmission Power

Offers selectable output power levels of 100mW and 500mW.

Flexible Frequency Selection

Allows arbitrary setting of frequency from 76M to 108M.

Microphone and Volume Control Features

Includes integrated microphone input and volume adjustment capabilities.

Circuit Principle

Main Specifications

All Configurations

Operation Instruction

Power Adjustment

Frequency Range Setting

Common Troubleshooting

After-sales Service

Disclaimer

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

The CZERF CZE-05B is a portable FM transmitter designed for high-fidelity and stable signal transmission. It is a multi-functional device that is easy to operate, aiming to provide a positive user experience.

Function Description

The CZE-05B functions as an FM transmitter, converting audio input into an FM radio signal for broadcast. It supports stereo audio input via a 3.5mm interface. The core of its functionality relies on the BH1415 integrated NC FM stereo radio transmitter chip from Japan ROHM Company. This chip incorporates a built-in PLL frequency PLL, audio pre-emphasis, a limiter, and a low-pass filter circuit to ensure high-fidelity and stable signal transmission.

The device's control panel is managed by an AT89C2051 and AT24C02, which work in conjunction with three power amplifiers (two 2SC3355 and one 2SC2053) to deliver a clear three-dimensional sound quality output. The audio signal, after being adjusted by a potentiometer, enters the BH1415 internal circuit, where it undergoes pre-emphasis, limiting, and low-pass filtering. A 7.6 MHz crystal vibration frequency oscillation circuit generates a 38 KHz subcarrier signal and a 19 KHz pilot signal. The audio signal and the 38 KHz subcarrier signal are balanced modulated by a multiplexer to produce a main signal (L+R) and a 38 KHz subcarrier signal (L-R) modulated by DSB. The composite signal, including the 19 KHz pilot signal, is then output.

The CZE-05B also features a microphone input via another 3.5mm interface. The microphone audio is amplified and combined with the composite signal. The two channels are directly modulated by a high-frequency oscillator composed of a variogram diode. Frequency control is achieved through touch keys, and the MCU (Microcontroller Unit) stabilizes the transmission frequency using the internal PLL circuit. After two stages of power amplification, the transmitting frequency generates an 800MW power output, which is then filtered by a low-pass filter (LC) and transmitted to the antenna. The MCU continuously transmits the current transmission frequency information to the user via an LCD display module.

Usage Features

The CZE-05B is designed for ease of use, with an LCD panel displaying the transmission frequency, making adjustments intuitive. Users can connect other hardware easily by identifying the interfaces.

Power Adjustment: The transmitter offers two output power settings: high power (H) at 500mW and low power (L) at 100mW. To adjust the power, the device must be powered off. Users press and hold the power button, then connect the DC12V power supply. After 3 seconds, release the button to enter power adjustment status, where the LCD will display "L" or "H" (defaulting to H). The up arrow key sets high power (H), and the down arrow key sets low power (L). Pressing the power button again confirms the selection and automatically transitions to the frequency range setting interface.

Frequency Range Setting: The device allows for setting both high-end and low-end frequencies.

1. High-end frequency setting: After power adjustment, pressing the power button again enters the frequency range setting status, and the LCD displays 108MHz (default high-end frequency). Users can adjust this frequency using the up and down arrow keys.
2. Low-end frequency setting: Once the high-end frequency is set, pressing the power button again enters the low-end frequency setting status, and the LCD displays 76.00 MHz (default low-end frequency). This can also be adjusted using the up and down arrow keys. After setting both frequency ranges, pressing the power button three times will finalize the settings, return to the background, and turn off the LCD display. It is crucial to note that the low-end frequency cannot be set higher than the high-end frequency; otherwise, the transmitter will cease to function.

Audio and Microphone Control: The device includes controls for audio input volume and microphone input volume, allowing users to balance sound levels for optimal transmission.

Shielding and Heat Dissipation: The CZE-05B features a closely designed structure that provides good shielding, preventing external signal induction from causing frequency drift. Its chassis is made of high-quality aluminum alloy, which is lightweight and offers excellent heat dissipation, ensuring continuous and stable operation.

Safety Precautions: Users are advised to read the manual carefully before use. Only professional engineers should perform repair work. It is critical not to power on the transmitter without connecting the antenna. The device should not be used in explosive environments (e.g., gas stations, areas with natural gas or steam) or placed in extremely dusty, damp, or hot locations. Users must operate the transmitter in accordance with local regulations and avoid using it during thunder/storm weather.

Maintenance Features

Troubleshooting: The manual provides a troubleshooting guide for common issues:

• Cannot boot: Check if the power outlet is working, if the power cord is plugged in correctly, and if the power adapter is functioning normally.
• Standing wave is greater: Verify that the antenna is connected and matches the device. Also, check if the antenna installation location is too close to a reflector.
• Transmitter distance is close: Investigate potential feeder loss, poor launch environment, incorrect output power adjustment, insufficient antenna installation height, antenna mismatch, or low receiver sensitivity.
• No power output: Ensure the output power is adjusted correctly and that the machine is not in standby mode or powered off.
• Audio muting: Check if the master volume is sufficiently high and if the input audio signal is normal.
• Microphone is silent: Confirm the microphone is normal, the microphone volume is not too low, it is a dynamic microphone, and it is properly plugged in.
• Sound quality is poor: Evaluate the microphone quality, input audio sound quality, antenna installation method, and ensure audio signal or machine volume is adjusted correctly.

After-sales Service: CZERF offers lifetime maintenance for the CZE-05B. Within 200 days of purchase, all repairs are free of charge, provided the issues are not due to:

1. Unauthorized disassembly or repair.
2. Mis-operation not following instructions.
3. Man-made damage (e.g., hits, crashes, water damage) or other non-product quality problems.
4. Damage caused by lightning or other force majeure.
5. Damage to accessories such as the product case, Li-ion battery, microphone, charger, audio cable, or charging cable, as these are not covered under free repair.

For products outside the free repair period or those with excluded circumstances, repairs are available at a very low cost. This includes lifetime maintenance for products beyond the free-repairing period and repairs for products damaged by human error at a minimal cost.

Disclaimer: The device complies with Part 15 of the FCC Rules for Class B digital devices, designed to provide reasonable protection against harmful interference in residential installations. It generates and radiates radio frequency energy, and if not installed and used according to instructions, it may cause harmful interference to radio communications. Users are encouraged to reorient or relocate the receiving antenna, increase separation between equipment and receiver, connect the equipment to a different circuit, or consult a radio/TV technician if interference occurs. Changes or modifications not expressly approved by the responsible party could void the user's authority to operate the equipment. The device's operation is subject to two conditions: it must not cause harmful interference, and it must accept any interference received, including undesired operation. Users are responsible for complying with local laws and regulations regarding wireless products; non-compliance absolves the manufacturer and distributors of responsibility. The equipment complies with FCC radiation exposure limits for an uncontrolled environment and should be installed and operated with a minimum distance of 20cm between the radiator and the body.

Czerf CZE-05B Specifications

General

Frequency Step Value	100 kHz
Stereo Separation	≥ 40 dB
SNR	≥ 60 dB
Modulation Frequency Deviation	±75 kHz
Power Supply	DC 12V
Modulation	FM
Input Voltage	DC 12V
Operating Temperature	-10°C to +50°C
Frequency Range	76~108MHz
Harmonic and Clutter Radiation	<=-60dB
Audio Distortion	0.2%
Frequency Response	50Hz~15000Hz