1. ആമുഖം
The PLJ-8LED-H is a cost-effective frequency display component featuring an 8-bit digital tube display. It is primarily designed for displaying frequency values in transceivers and other electronic equipment, and can also be utilized for general frequency measurement tasks. This module is characterized by its compact and delicate design, reliable performance, clear visual effect, and economical cost.

ചിത്രം 1: മുൻഭാഗം view of the PLJ-8LED-H module with the display showing '29.600.000'. This image highlights the dual frequency design and preset modes.
2 സുരക്ഷാ വിവരങ്ങൾ
- വൈദ്യുതി വിതരണം വോളിയം ഉറപ്പാക്കുകtage is within the specified range (DC 9V ~ 15V) to prevent damage.
- Observe correct polarity when connecting the DC power input. The module includes reverse polarity protection, but proper connection is always recommended.
- Avoid touching the circuit board components while the module is powered on.
- Do not expose the module to moisture, extreme temperatures, or corrosive environments.
- Handle with care to prevent physical damage to the display or circuit board.
3. ഉൽപ്പന്നം കഴിഞ്ഞുview ഫീച്ചറുകളും
The PLJ-8LED-H module incorporates advanced design for precise frequency measurement and display.
പ്രധാന സവിശേഷതകൾ:
- Microchip PIC16F648A: Utilizes a 2.4 GHz frequency meter based on the PIC16F648A microcontroller.
- Temperature-Compensated Crystal Oscillator: Employs a 2.5 ppm VC-TCXO (Voltage Controlled Temperature-Compensated Crystal Oscillator) for enhanced accuracy.
- Precise Time Algorithm: Features unique gate control and a precise non-timed interrupt algorithm.
- Adjustable Gate Time: Offers gate (display refresh) times of 0.01 seconds, 0.1 seconds, and 1.0 seconds for real-time frequency display.
- Three-Channel Measurement: Supports single-ended input design with three frequency measurement channels: Low Channel, High Channel, and Auto Channel.
- Dual Frequency Design: Allows separate presetting of value and IF (Intermediate Frequency) / down modes.
- High Brightness Digital Display: Equipped with eight 0.56-inch high-brightness digital LED displays.
- ക്രമീകരിക്കാവുന്ന തെളിച്ചം: Eight levels of adjustable display brightness.
- ലളിതമായ പ്രവർത്തനം: Features a simple and reasonable circuit structure with two-button control.
- Automatic Settings Save: Automatically saves settings, which are recalled directly upon boot-up.

ചിത്രം 2: കോണാകൃതിയിലുള്ളത് view of the PLJ-8LED-H module, emphasizing its simple circuit structure and two-button control.
4 സ്പെസിഫിക്കേഷനുകൾ
| ഫീച്ചർ | വിവരണം |
|---|---|
| മോഡൽ | PLJ-8LED-H |
| ഡിസ്പ്ലേ തരം | 8-bit 0.56-inch Digital LED (Red or Blue font options) |
| Gate Time (Display Refresh) | 0.01 S / 0.10 S / 1.0 S |
| അളക്കൽ ചാനലുകൾ | Low Channel, High Channel, Auto Channel (low impedance) |
| Low Channel Measuring Range | 0.1 MHz ~ 60 MHz |
| Low Channel Accuracy | ± 100Hz (0.01s gate), ± 10Hz (0.1s gate), ± 1Hz (1.0s gate) |
| Low Channel Sensitivity | 0.1-10 MHz: >60mVPP; 10-60 MHz: >60mVPP |
| High Channel Measuring Range | 20 MHz ~ 2.4 GHz (divided by 64) |
| High Channel Accuracy | ± 6400Hz (0.01s gate), ± 640Hz (0.1s gate), ± 64Hz (1.0s gate) |
| High Channel Sensitivity | 20-30 MHz: >100mVPP; 30-60 MHz: >50mVPP |
| IF Settings | Independent double-IF design, 100 Hz min step, 0 ~ 99.9999 MHz range, increase/decrease mode |
| ഫ്രീക്വൻസി റഫറൻസ് | 5032 package 13.000MHz VC-TCXO, ± 2.5 ppm stability |
| ഓപ്പറേറ്റിംഗ് വോളിയംtage | DC 9V ~ 15V (with reverse polarity protection) |
| നിലവിലെ ഉപഭോഗം | Max 160 mA (DC12V, red LED, max brightness) |
| ഡിസ്പ്ലേ അക്കങ്ങൾ | Highest display eight digits |
| തെളിച്ചം ക്രമീകരിക്കൽ | Eight adjustable levels (factory set to maximum) |
| Physical Dimensions (LxWxH) | 125.5 mm x 25.5 mm x 21.5 mm |
| മൊത്തം ഭാരം | ഏകദേശം 46 ഗ്രാം |
| Onboard Interfaces | DC IN (HX2.54-2P socket), RF IN (HX2.54-2P socket), ICSP (2.54-6P Pin) |

ചിത്രം 3: താഴെ view of the PLJ-8LED-H PCB, revealing the electronic components and layout.
5. സജ്ജീകരണം
5.1 പാക്കേജ് ഉള്ളടക്കം
തുടരുന്നതിന് മുമ്പ്, എല്ലാ ഘടകങ്ങളും ഉണ്ടെന്ന് ഉറപ്പാക്കുക:
- 1 x PLJ-8LED-H Frequency Counter Module
- 2 x Connecting Cables (for power and signal input)

Figure 4: The PLJ-8LED-H module packaged with two connecting cables.
5.2 പവർ കണക്ഷൻ
- Locate the DC IN (Power Interface) on the module, which is an HX2.54-2P socket.
- Connect one of the provided cables to the DC IN socket.
- Connect the other end of this cable to a stable DC power source providing 9V to 15V. Ensure correct polarity.
5.3 Signal Input Connection
- Identify the RF IN (signal input) on the module, also an HX2.54-2P socket.
- Connect the second provided cable to the RF IN socket.
- Connect the other end of this cable to the signal source whose frequency you wish to measure.
6. പ്രവർത്തന നിർദ്ദേശങ്ങൾ
The module features two buttons for control and configuration.
6.1 Gate Time Selection
The gate time determines how frequently the display refreshes and impacts measurement accuracy. Shorter gate times provide faster updates but lower accuracy, while longer gate times offer higher accuracy with slower updates.
- Available gate times: 0.01 seconds, 0.1 seconds, 1.0 seconds.
- Refer to the specifications for accuracy corresponding to each gate time.
6.2 Measurement Channel Selection
The module supports three measurement channels:
- Low Channel: For frequencies between 0.1 MHz and 60 MHz.
- High Channel: For frequencies between 20 MHz and 2.4 GHz. This channel divides the input frequency by 64.
- Auto Channel: Automatically selects between the low and high channels based on the input signal frequency, with a threshold of 60 MHz. If the input signal amplitude is insufficient for the Auto Channel to correctly identify frequencies above 60 MHz, manual selection of the High Channel may be necessary.
6.3 IF Settings
The module features an independent double-IF design, allowing for adjustment of intermediate frequencies.
- The minimum frequency step for adjustment is 100 Hz.
- The frequency range for IF settings is 0 ~ 99.9999 MHz.
- You can set the IF frequency mode to either increase or decrease.
6.4 ഡിസ്പ്ലേ ബ്രൈറ്റ്നസ് അഡ്ജസ്റ്റ്മെന്റ്
The 8-bit LED display's brightness can be adjusted through eight levels. The factory default is set to maximum brightness.
6.5 സേവിംഗ് സെറ്റിംഗ്സ്
All configured settings are automatically saved and will be loaded directly when the module is powered on again.

ചിത്രം 5: വശം view of the PLJ-8LED-H module, showing the display, control buttons, and mounting holes.
7 ഉപയോക്തൃ നുറുങ്ങുകൾ
- Measuring FM Broadcast Frequencies (88-108 MHz): Yes, the PLJ-8LED-H module can measure frequencies within the FM broadcast band (88 to 108 MHz). For these frequencies, you should use the 'High Channel' setting, as the 'Auto Channel' typically switches to the high range above 60 MHz, but manual selection ensures optimal performance for signals in this range. The High Channel supports measurements up to 2.4 GHz.
- Optimizing Accuracy: For the most accurate readings, especially for stable signals, select the 1.0-second gate time. For faster, less critical measurements, use the 0.01-second or 0.1-second gate times.
- സിഗ്നൽ ശക്തി: If you encounter unstable readings, ensure your input signal has sufficient amplitude. Refer to the sensitivity specifications for each channel.
8. പ്രശ്നപരിഹാരം
- No Display/Module Not Powering On:
- പവർ സപ്ലൈ വോള്യം പരിശോധിക്കുകtagഇ (ഡിസി 9V-15V).
- Verify power cable connections and polarity.
- കൃത്യമല്ലാത്തതോ അസ്ഥിരമായതോ ആയ വായനകൾ:
- Ensure the correct measurement channel (Low, High, Auto) is selected for the frequency range.
- Increase the gate time (e.g., to 1.0 seconds) for higher accuracy.
- Check the input signal strength and quality. Weak or noisy signals can lead to unstable readings.
- Verify signal input cable connections.
- Display Too Dim/Bright:
- Adjust the display brightness using the control buttons.
- Module Not Responding to Buttons:
- Power cycle the module (turn off and on).
- Ensure buttons are not physically stuck.
9. പരിപാലനം
- വൃത്തിയാക്കൽ: Use a soft, dry cloth to clean the module. Do not use liquid cleaners or solvents.
- സംഭരണം: ഉപയോഗത്തിലില്ലാത്തപ്പോൾ മൊഡ്യൂൾ വരണ്ടതും പൊടിയില്ലാത്തതുമായ അന്തരീക്ഷത്തിൽ സൂക്ഷിക്കുക.
- ഘടക പരിശോധന: Periodically inspect the circuit board for any signs of damage, loose connections, or overheating components.
- ഫേംവെയർ: The ICSP interface is for programming. Firmware updates are typically not user-serviceable and should only be performed by qualified personnel if necessary.
10. വാറൻ്റിയും പിന്തുണയും
For warranty information and technical support, please contact your retailer or the manufacturer directly. Keep your purchase receipt as proof of purchase.





